diff --git a/toolchain/driver/driver.cpp b/toolchain/driver/driver.cpp
index cd388b062c14b..6b6e8714753f1 100644
--- a/toolchain/driver/driver.cpp
+++ b/toolchain/driver/driver.cpp
@@ -337,6 +337,14 @@ Excludes files with the given prefix from dumps.
 )""",
         },
         [&](auto& arg_b) { arg_b.Set(&exclude_dump_file_prefix); });
+    b.AddFlag(
+        {
+            .name = "debug-info",
+            .help = R"""(
+Emit DWARF debug information.
+)""",
+        },
+        [&](auto& arg_b) { arg_b.Set(&include_debug_info); });
   }
 
   Phase phase;
@@ -358,6 +366,7 @@ Excludes files with the given prefix from dumps.
   bool preorder_parse_tree = false;
   bool builtin_sem_ir = false;
   bool prelude_import = false;
+  bool include_debug_info = false;
 
   llvm::StringRef exclude_dump_file_prefix;
 };
@@ -523,6 +532,12 @@ auto Driver::ValidateCompileOptions(const CompileOptions& options) const
                       << options.phase << "'.\n";
         return false;
       }
+      if (options.include_debug_info) {
+        error_stream_
+            << "ERROR: Requested debug info but compile phase is limited to '"
+            << options.phase << "'.\n";
+        return false;
+      }
       [[fallthrough]];
     case Phase::Lower:
     case Phase::CodeGen:
@@ -676,8 +691,9 @@ class Driver::CompilationUnit {
       // TODO: Consider disabling instruction naming by default if we're not
       // producing textual LLVM IR.
       SemIR::InstNamer inst_namer(*tokens_, *parse_tree_, *sem_ir_);
-      module_ = Lower::LowerToLLVM(*llvm_context_, input_filename_, *sem_ir_,
-                                   &inst_namer, vlog_stream_);
+      module_ = Lower::LowerToLLVM(*llvm_context_, options_.include_debug_info,
+                                   input_filename_, *sem_ir_, &inst_namer,
+                                   vlog_stream_);
     });
     if (vlog_stream_) {
       CARBON_VLOG() << "*** llvm::Module ***\n";
diff --git a/toolchain/driver/testdata/fail_flags.carbon b/toolchain/driver/testdata/fail_flags.carbon
new file mode 100644
index 0000000000000..3b68f5118f11c
--- /dev/null
+++ b/toolchain/driver/testdata/fail_flags.carbon
@@ -0,0 +1,13 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// ARGS: compile --debug-info --phase=check %s
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/driver/testdata/fail_flags.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/driver/testdata/fail_flags.carbon
+// CHECK:STDERR: ERROR: Requested debug info but compile phase is limited to 'check'.
+//
diff --git a/toolchain/lower/file_context.cpp b/toolchain/lower/file_context.cpp
index d938ca81f8b3e..397c86ba325b1 100644
--- a/toolchain/lower/file_context.cpp
+++ b/toolchain/lower/file_context.cpp
@@ -21,11 +21,17 @@
 namespace Carbon::Lower {
 
 FileContext::FileContext(llvm::LLVMContext& llvm_context,
-                         llvm::StringRef module_name, const SemIR::File& sem_ir,
+                         bool include_debug_info, llvm::StringRef module_name,
+                         const SemIR::File& sem_ir,
                          const SemIR::InstNamer* inst_namer,
                          llvm::raw_ostream* vlog_stream)
     : llvm_context_(&llvm_context),
       llvm_module_(std::make_unique<llvm::Module>(module_name, llvm_context)),
+      di_builder_(*llvm_module_),
+      di_compile_unit_(
+          include_debug_info
+              ? BuildDICompileUnit(module_name, *llvm_module_, di_builder_)
+              : nullptr),
       sem_ir_(&sem_ir),
       inst_namer_(inst_namer),
       vlog_stream_(vlog_stream) {
@@ -80,6 +86,25 @@ auto FileContext::Run() -> std::unique_ptr<llvm::Module> {
   return std::move(llvm_module_);
 }
 
+auto FileContext::BuildDICompileUnit(llvm::StringRef module_name,
+                                     llvm::Module& llvm_module,
+                                     llvm::DIBuilder& di_builder)
+    -> llvm::DICompileUnit* {
+  llvm_module.addModuleFlag(llvm::Module::Max, "Dwarf Version", 5);
+  llvm_module.addModuleFlag(llvm::Module::Warning, "Debug Info Version",
+                            llvm::DEBUG_METADATA_VERSION);
+  // FIXME: Include directory path in the compile_unit_file.
+  llvm::DIFile* compile_unit_file = di_builder.createFile(module_name, "");
+  // FIXME: Introduce a new language code for Carbon. C works well for now since
+  // it's something debuggers will already know/have support for at least.
+  // Probably have to bump to C++ at some point for virtual functions,
+  // templates, etc.
+  return di_builder.createCompileUnit(llvm::dwarf::DW_LANG_C, compile_unit_file,
+                                      "carbon",
+                                      /*isOptimized=*/false, /*Flags=*/"",
+                                      /*RV=*/0);
+}
+
 auto FileContext::GetGlobal(SemIR::InstId inst_id) -> llvm::Value* {
   auto inst = sem_ir().insts().Get(inst_id);
 
diff --git a/toolchain/lower/file_context.h b/toolchain/lower/file_context.h
index dbc5607576e27..844092cc70694 100644
--- a/toolchain/lower/file_context.h
+++ b/toolchain/lower/file_context.h
@@ -6,6 +6,7 @@
 #define CARBON_TOOLCHAIN_LOWER_FILE_CONTEXT_H_
 
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "toolchain/sem_ir/file.h"
@@ -16,7 +17,7 @@ namespace Carbon::Lower {
 // Context and shared functionality for lowering handlers.
 class FileContext {
  public:
-  explicit FileContext(llvm::LLVMContext& llvm_context,
+  explicit FileContext(llvm::LLVMContext& llvm_context, bool include_debug_info,
                        llvm::StringRef module_name, const SemIR::File& sem_ir,
                        const SemIR::InstNamer* inst_namer,
                        llvm::raw_ostream* vlog_stream);
@@ -25,6 +26,11 @@ class FileContext {
   // the main execution loop.
   auto Run() -> std::unique_ptr<llvm::Module>;
 
+  // Create the DICompileUnit metadata for this compilation.
+  auto BuildDICompileUnit(llvm::StringRef module_name,
+                          llvm::Module& llvm_module,
+                          llvm::DIBuilder& di_builder) -> llvm::DICompileUnit*;
+
   // Gets a callable's function. Returns nullptr for a builtin.
   auto GetFunction(SemIR::FunctionId function_id) -> llvm::Function* {
     return functions_[function_id.index];
@@ -85,6 +91,12 @@ class FileContext {
   llvm::LLVMContext* llvm_context_;
   std::unique_ptr<llvm::Module> llvm_module_;
 
+  // State for building the LLVM IR debug info metadata.
+  llvm::DIBuilder di_builder_;
+
+  // The DICompileUnit, if any - null implies debug info is not being emitted.
+  llvm::DICompileUnit* di_compile_unit_;
+
   // The input SemIR.
   const SemIR::File* const sem_ir_;
 
diff --git a/toolchain/lower/handle.cpp b/toolchain/lower/handle.cpp
index 656bec92d891d..f24cb6dcfcbb0 100644
--- a/toolchain/lower/handle.cpp
+++ b/toolchain/lower/handle.cpp
@@ -7,6 +7,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Type.h"
 #include "llvm/IR/Value.h"
 #include "llvm/Support/Casting.h"
diff --git a/toolchain/lower/lower.cpp b/toolchain/lower/lower.cpp
index 82d06216a237f..22c65b857a732 100644
--- a/toolchain/lower/lower.cpp
+++ b/toolchain/lower/lower.cpp
@@ -8,12 +8,13 @@
 
 namespace Carbon::Lower {
 
-auto LowerToLLVM(llvm::LLVMContext& llvm_context, llvm::StringRef module_name,
-                 const SemIR::File& sem_ir, const SemIR::InstNamer* inst_namer,
+auto LowerToLLVM(llvm::LLVMContext& llvm_context, bool include_debug_info,
+                 llvm::StringRef module_name, const SemIR::File& sem_ir,
+                 const SemIR::InstNamer* inst_namer,
                  llvm::raw_ostream* vlog_stream)
     -> std::unique_ptr<llvm::Module> {
-  FileContext context(llvm_context, module_name, sem_ir, inst_namer,
-                      vlog_stream);
+  FileContext context(llvm_context, include_debug_info, module_name, sem_ir,
+                      inst_namer, vlog_stream);
   return context.Run();
 }
 
diff --git a/toolchain/lower/lower.h b/toolchain/lower/lower.h
index 66ec79d80de7c..36ac71a059166 100644
--- a/toolchain/lower/lower.h
+++ b/toolchain/lower/lower.h
@@ -13,8 +13,9 @@
 namespace Carbon::Lower {
 
 // Lowers SemIR to LLVM IR.
-auto LowerToLLVM(llvm::LLVMContext& llvm_context, llvm::StringRef module_name,
-                 const SemIR::File& sem_ir, const SemIR::InstNamer* inst_namer,
+auto LowerToLLVM(llvm::LLVMContext& llvm_context, bool include_debug_info,
+                 llvm::StringRef module_name, const SemIR::File& sem_ir,
+                 const SemIR::InstNamer* inst_namer,
                  llvm::raw_ostream* vlog_stream)
     -> std::unique_ptr<llvm::Module>;
 
diff --git a/toolchain/lower/testdata/alias/local.carbon b/toolchain/lower/testdata/alias/local.carbon
index 24f6f83789768..c6a86267b4b65 100644
--- a/toolchain/lower/testdata/alias/local.carbon
+++ b/toolchain/lower/testdata/alias/local.carbon
@@ -24,3 +24,11 @@ fn F() -> i32 {
 // CHECK:STDOUT:   %.loc14 = load i32, ptr %a.var, align 4
 // CHECK:STDOUT:   ret i32 %.loc14
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "local.carbon", directory: "")
diff --git a/toolchain/lower/testdata/array/array_in_place.carbon b/toolchain/lower/testdata/array/array_in_place.carbon
index 0fa4a80255a09..4080e7d5a7633 100644
--- a/toolchain/lower/testdata/array/array_in_place.carbon
+++ b/toolchain/lower/testdata/array/array_in_place.carbon
@@ -28,3 +28,11 @@ fn G() {
 // CHECK:STDOUT:   call void @F(ptr %.loc14_42.5.array.index)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "array_in_place.carbon", directory: "")
diff --git a/toolchain/lower/testdata/array/assign_return_value.carbon b/toolchain/lower/testdata/array/assign_return_value.carbon
index 9a21a1bf06647..768e1998116b6 100644
--- a/toolchain/lower/testdata/array/assign_return_value.carbon
+++ b/toolchain/lower/testdata/array/assign_return_value.carbon
@@ -47,3 +47,11 @@ fn Run() {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "assign_return_value.carbon", directory: "")
diff --git a/toolchain/lower/testdata/array/base.carbon b/toolchain/lower/testdata/array/base.carbon
index eb5174c329ad7..cca4b4c5cd582 100644
--- a/toolchain/lower/testdata/array/base.carbon
+++ b/toolchain/lower/testdata/array/base.carbon
@@ -68,3 +68,11 @@ fn Run() {
 // CHECK:STDOUT: uselistorder ptr @llvm.memcpy.p0.p0.i64, { 3, 2, 1, 0 }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "base.carbon", directory: "")
diff --git a/toolchain/lower/testdata/array/function_param.carbon b/toolchain/lower/testdata/array/function_param.carbon
index 1759f8df48686..c2fff5de11b86 100644
--- a/toolchain/lower/testdata/array/function_param.carbon
+++ b/toolchain/lower/testdata/array/function_param.carbon
@@ -43,3 +43,11 @@ fn G() -> i32 {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "function_param.carbon", directory: "")
diff --git a/toolchain/lower/testdata/basics/empty.carbon b/toolchain/lower/testdata/basics/empty.carbon
index ef5076eab179c..de98d7b44b377 100644
--- a/toolchain/lower/testdata/basics/empty.carbon
+++ b/toolchain/lower/testdata/basics/empty.carbon
@@ -10,3 +10,11 @@
 
 // CHECK:STDOUT: ; ModuleID = 'empty.carbon'
 // CHECK:STDOUT: source_filename = "empty.carbon"
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "empty.carbon", directory: "")
diff --git a/toolchain/lower/testdata/basics/false_true.carbon b/toolchain/lower/testdata/basics/false_true.carbon
index 650d65e4fb3dc..5e726303a822a 100644
--- a/toolchain/lower/testdata/basics/false_true.carbon
+++ b/toolchain/lower/testdata/basics/false_true.carbon
@@ -28,3 +28,11 @@ fn T() -> bool {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i1 true
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "false_true.carbon", directory: "")
diff --git a/toolchain/lower/testdata/basics/int_types.carbon b/toolchain/lower/testdata/basics/int_types.carbon
index adeb6e701d265..099a23f66427f 100644
--- a/toolchain/lower/testdata/basics/int_types.carbon
+++ b/toolchain/lower/testdata/basics/int_types.carbon
@@ -35,3 +35,11 @@ fn F_u65536(a: u65536) -> u65536 { return a; }
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i65536 %a
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "int_types.carbon", directory: "")
diff --git a/toolchain/lower/testdata/basics/numeric_literals.carbon b/toolchain/lower/testdata/basics/numeric_literals.carbon
index d6dbe772fd982..1f50d8ac58acb 100644
--- a/toolchain/lower/testdata/basics/numeric_literals.carbon
+++ b/toolchain/lower/testdata/basics/numeric_literals.carbon
@@ -59,3 +59,11 @@ fn F() {
 // CHECK:STDOUT: uselistorder ptr @llvm.memcpy.p0.p0.i64, { 1, 0 }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "numeric_literals.carbon", directory: "")
diff --git a/toolchain/lower/testdata/basics/type_values.carbon b/toolchain/lower/testdata/basics/type_values.carbon
index 0c3eb0c00c5e9..385fbeaec9753 100644
--- a/toolchain/lower/testdata/basics/type_values.carbon
+++ b/toolchain/lower/testdata/basics/type_values.carbon
@@ -42,3 +42,11 @@ fn F64() -> type {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret %type zeroinitializer
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "type_values.carbon", directory: "")
diff --git a/toolchain/lower/testdata/basics/zero.carbon b/toolchain/lower/testdata/basics/zero.carbon
index ced60aa37b4d6..a9f3235c6b3de 100644
--- a/toolchain/lower/testdata/basics/zero.carbon
+++ b/toolchain/lower/testdata/basics/zero.carbon
@@ -19,3 +19,11 @@ fn Main() -> i32 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i32 0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "zero.carbon", directory: "")
diff --git a/toolchain/lower/testdata/builtins/float.carbon b/toolchain/lower/testdata/builtins/float.carbon
index ef3c4f7c493c3..9272cd5f03909 100644
--- a/toolchain/lower/testdata/builtins/float.carbon
+++ b/toolchain/lower/testdata/builtins/float.carbon
@@ -109,3 +109,11 @@ fn TestGreaterEq(a: f64, b: f64) -> bool { return GreaterEq(a, b); }
 // CHECK:STDOUT:   %float.greater_eq = fcmp oge double %a, %b
 // CHECK:STDOUT:   ret i1 %float.greater_eq
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "float.carbon", directory: "")
diff --git a/toolchain/lower/testdata/builtins/int.carbon b/toolchain/lower/testdata/builtins/int.carbon
index 2ac1dbf323dcb..6821a5d5657b0 100644
--- a/toolchain/lower/testdata/builtins/int.carbon
+++ b/toolchain/lower/testdata/builtins/int.carbon
@@ -172,3 +172,11 @@ fn TestGreaterEq(a: i32, b: i32) -> bool { return GreaterEq(a, b); }
 // CHECK:STDOUT:   %int.greater_eq = icmp sge i32 %a, %b
 // CHECK:STDOUT:   ret i1 %int.greater_eq
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "int.carbon", directory: "")
diff --git a/toolchain/lower/testdata/builtins/method_vs_nonmethod.carbon b/toolchain/lower/testdata/builtins/method_vs_nonmethod.carbon
index fa5065c0cbd5e..7a12846df919c 100644
--- a/toolchain/lower/testdata/builtins/method_vs_nonmethod.carbon
+++ b/toolchain/lower/testdata/builtins/method_vs_nonmethod.carbon
@@ -28,3 +28,11 @@ fn TestAddMethod(a: i32, b: i32) -> i32 { return a.(AddMethod)(b); }
 // CHECK:STDOUT:   %int.sadd = add i32 %a, %b
 // CHECK:STDOUT:   ret i32 %int.sadd
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "method_vs_nonmethod.carbon", directory: "")
diff --git a/toolchain/lower/testdata/builtins/overloaded_operator.carbon b/toolchain/lower/testdata/builtins/overloaded_operator.carbon
index f732a993c3107..344d6492a952e 100644
--- a/toolchain/lower/testdata/builtins/overloaded_operator.carbon
+++ b/toolchain/lower/testdata/builtins/overloaded_operator.carbon
@@ -30,3 +30,11 @@ fn AddThreeIntegers(a: i32, b: i32, c: i32) -> i32 {
 // CHECK:STDOUT:   %int.sadd.loc18_16 = add i32 %.loc18_12.4, %c
 // CHECK:STDOUT:   ret i32 %int.sadd.loc18_16
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "overloaded_operator.carbon", directory: "")
diff --git a/toolchain/lower/testdata/builtins/print.carbon b/toolchain/lower/testdata/builtins/print.carbon
index d22897904bb0d..7dfd0270f9272 100644
--- a/toolchain/lower/testdata/builtins/print.carbon
+++ b/toolchain/lower/testdata/builtins/print.carbon
@@ -24,3 +24,11 @@ fn Main() {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: declare i32 @printf(ptr, ...)
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "print.carbon", directory: "")
diff --git a/toolchain/lower/testdata/builtins/types.carbon b/toolchain/lower/testdata/builtins/types.carbon
index 81b08095a348a..339dbfd802c94 100644
--- a/toolchain/lower/testdata/builtins/types.carbon
+++ b/toolchain/lower/testdata/builtins/types.carbon
@@ -31,3 +31,11 @@ fn F() {
 // CHECK:STDOUT:   store i1 false, ptr %b.var, align 1
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "types.carbon", directory: "")
diff --git a/toolchain/lower/testdata/builtins/uint.carbon b/toolchain/lower/testdata/builtins/uint.carbon
index d57b6367873de..854d6c4fe2ce2 100644
--- a/toolchain/lower/testdata/builtins/uint.carbon
+++ b/toolchain/lower/testdata/builtins/uint.carbon
@@ -172,3 +172,11 @@ fn TestGreaterEq(a: u64, b: u64) -> bool { return GreaterEq(a, b); }
 // CHECK:STDOUT:   %int.greater_eq = icmp uge i64 %a, %b
 // CHECK:STDOUT:   ret i1 %int.greater_eq
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "uint.carbon", directory: "")
diff --git a/toolchain/lower/testdata/class/adapt.carbon b/toolchain/lower/testdata/class/adapt.carbon
index 2bec22d6c19be..4712675af10ac 100644
--- a/toolchain/lower/testdata/class/adapt.carbon
+++ b/toolchain/lower/testdata/class/adapt.carbon
@@ -89,6 +89,14 @@ fn DoStuff(a: Int) -> Int {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "adapt_class.carbon", directory: "")
 // CHECK:STDOUT: ; ModuleID = 'adapt_int.carbon'
 // CHECK:STDOUT: source_filename = "adapt_int.carbon"
 // CHECK:STDOUT:
@@ -96,3 +104,11 @@ fn DoStuff(a: Int) -> Int {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i32 %a
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "adapt_int.carbon", directory: "")
diff --git a/toolchain/lower/testdata/class/base.carbon b/toolchain/lower/testdata/class/base.carbon
index 0eebdcb503123..6efb90d24dc73 100644
--- a/toolchain/lower/testdata/class/base.carbon
+++ b/toolchain/lower/testdata/class/base.carbon
@@ -68,3 +68,11 @@ fn Convert(p: Derived*) -> Base* {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "base.carbon", directory: "")
diff --git a/toolchain/lower/testdata/class/basic.carbon b/toolchain/lower/testdata/class/basic.carbon
index be0d3d12df96c..cdf6a8ff9053e 100644
--- a/toolchain/lower/testdata/class/basic.carbon
+++ b/toolchain/lower/testdata/class/basic.carbon
@@ -32,3 +32,11 @@ fn Run() {
 // CHECK:STDOUT:   call void @F(ptr %d.var, ptr %c.var)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "basic.carbon", directory: "")
diff --git a/toolchain/lower/testdata/class/field.carbon b/toolchain/lower/testdata/class/field.carbon
index 9ff92362aa3cb..1277a47a4cc5e 100644
--- a/toolchain/lower/testdata/class/field.carbon
+++ b/toolchain/lower/testdata/class/field.carbon
@@ -46,3 +46,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT:   %F.call = call i32 @F(ptr %c.var)
 // CHECK:STDOUT:   ret i32 %F.call
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "field.carbon", directory: "")
diff --git a/toolchain/lower/testdata/class/method.carbon b/toolchain/lower/testdata/class/method.carbon
index a52aba42fd323..ba7dc13c070e5 100644
--- a/toolchain/lower/testdata/class/method.carbon
+++ b/toolchain/lower/testdata/class/method.carbon
@@ -33,3 +33,11 @@ fn F(p: C*) {
 // CHECK:STDOUT:   call void @Set(ptr %p, i32 %Get.call)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "method.carbon", directory: "")
diff --git a/toolchain/lower/testdata/class/self.carbon b/toolchain/lower/testdata/class/self.carbon
index 7b5f3746abd28..b069cf06afe37 100644
--- a/toolchain/lower/testdata/class/self.carbon
+++ b/toolchain/lower/testdata/class/self.carbon
@@ -39,3 +39,11 @@ fn C.Set[addr self: C*]() {
 // CHECK:STDOUT:   store i32 1, ptr %.loc23_10.a, align 4
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "self.carbon", directory: "")
diff --git a/toolchain/lower/testdata/class/value_access.carbon b/toolchain/lower/testdata/class/value_access.carbon
index 83fce738bc555..3a97d32f5d989 100644
--- a/toolchain/lower/testdata/class/value_access.carbon
+++ b/toolchain/lower/testdata/class/value_access.carbon
@@ -42,3 +42,11 @@ fn F(c: C) -> i32 {
 // CHECK:STDOUT:   %.loc19_13.tuple.index.load = load i32, ptr %.loc19_13.tuple.index, align 4
 // CHECK:STDOUT:   ret i32 %.loc19_13.tuple.index.load
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "value_access.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/empty_struct.carbon b/toolchain/lower/testdata/function/call/empty_struct.carbon
index bc3e91a1000ec..ee8cd679501dd 100644
--- a/toolchain/lower/testdata/function/call/empty_struct.carbon
+++ b/toolchain/lower/testdata/function/call/empty_struct.carbon
@@ -30,3 +30,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @Echo()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "empty_struct.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/empty_tuple.carbon b/toolchain/lower/testdata/function/call/empty_tuple.carbon
index 33f4ed2b16d31..1abaae24d5685 100644
--- a/toolchain/lower/testdata/function/call/empty_tuple.carbon
+++ b/toolchain/lower/testdata/function/call/empty_tuple.carbon
@@ -30,3 +30,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @Echo()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "empty_tuple.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/i32.carbon b/toolchain/lower/testdata/function/call/i32.carbon
index bb89e3befe919..2e29e66739986 100644
--- a/toolchain/lower/testdata/function/call/i32.carbon
+++ b/toolchain/lower/testdata/function/call/i32.carbon
@@ -31,3 +31,11 @@ fn Main() {
 // CHECK:STDOUT:   store i32 %Echo.call, ptr %b.var, align 4
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "i32.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/implicit_empty_tuple_as_arg.carbon b/toolchain/lower/testdata/function/call/implicit_empty_tuple_as_arg.carbon
index ed9267995c621..58325fb8bc104 100644
--- a/toolchain/lower/testdata/function/call/implicit_empty_tuple_as_arg.carbon
+++ b/toolchain/lower/testdata/function/call/implicit_empty_tuple_as_arg.carbon
@@ -38,3 +38,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @Bar()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "implicit_empty_tuple_as_arg.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/params_one.carbon b/toolchain/lower/testdata/function/call/params_one.carbon
index d3d2b266676b2..9e1852697a90c 100644
--- a/toolchain/lower/testdata/function/call/params_one.carbon
+++ b/toolchain/lower/testdata/function/call/params_one.carbon
@@ -27,3 +27,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @Foo(i32 1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "params_one.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/params_one_comma.carbon b/toolchain/lower/testdata/function/call/params_one_comma.carbon
index 4aa6e9625f882..8431533d47807 100644
--- a/toolchain/lower/testdata/function/call/params_one_comma.carbon
+++ b/toolchain/lower/testdata/function/call/params_one_comma.carbon
@@ -29,3 +29,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @Foo(i32 1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "params_one_comma.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/params_two.carbon b/toolchain/lower/testdata/function/call/params_two.carbon
index 65b46932c1eed..343414bf62b0b 100644
--- a/toolchain/lower/testdata/function/call/params_two.carbon
+++ b/toolchain/lower/testdata/function/call/params_two.carbon
@@ -27,3 +27,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @Foo(i32 1, i32 2)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "params_two.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/params_two_comma.carbon b/toolchain/lower/testdata/function/call/params_two_comma.carbon
index 1661fa6e2dbf1..ce82f627039d4 100644
--- a/toolchain/lower/testdata/function/call/params_two_comma.carbon
+++ b/toolchain/lower/testdata/function/call/params_two_comma.carbon
@@ -29,3 +29,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @Foo(i32 1, i32 2)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "params_two_comma.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/params_zero.carbon b/toolchain/lower/testdata/function/call/params_zero.carbon
index 3acb0f8c4d6d8..3f1e052b5c496 100644
--- a/toolchain/lower/testdata/function/call/params_zero.carbon
+++ b/toolchain/lower/testdata/function/call/params_zero.carbon
@@ -27,3 +27,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @Foo()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "params_zero.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/return_implicit.carbon b/toolchain/lower/testdata/function/call/return_implicit.carbon
index 0ba263d46f72a..61682273d0e3b 100644
--- a/toolchain/lower/testdata/function/call/return_implicit.carbon
+++ b/toolchain/lower/testdata/function/call/return_implicit.carbon
@@ -30,3 +30,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @MakeImplicitEmptyTuple()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "return_implicit.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/struct_param.carbon b/toolchain/lower/testdata/function/call/struct_param.carbon
index 9315be9fa056b..f184dc850485d 100644
--- a/toolchain/lower/testdata/function/call/struct_param.carbon
+++ b/toolchain/lower/testdata/function/call/struct_param.carbon
@@ -29,3 +29,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @F({ i32 } { i32 1 }, ptr @struct.3.loc14_4.3)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "struct_param.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/tuple_param.carbon b/toolchain/lower/testdata/function/call/tuple_param.carbon
index 1fb50b91186c5..f155cef1f0012 100644
--- a/toolchain/lower/testdata/function/call/tuple_param.carbon
+++ b/toolchain/lower/testdata/function/call/tuple_param.carbon
@@ -29,3 +29,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @F({ i32 } { i32 1 }, ptr @tuple.3.loc14_4.3)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "tuple_param.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/tuple_param_with_return_slot.carbon b/toolchain/lower/testdata/function/call/tuple_param_with_return_slot.carbon
index b8b928e1b7252..d00e90501acbd 100644
--- a/toolchain/lower/testdata/function/call/tuple_param_with_return_slot.carbon
+++ b/toolchain/lower/testdata/function/call/tuple_param_with_return_slot.carbon
@@ -46,3 +46,11 @@ fn Main() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder i32 1, { 3, 0, 1, 2 }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "tuple_param_with_return_slot.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/call/var_param.carbon b/toolchain/lower/testdata/function/call/var_param.carbon
index 941dcbbc99a3e..6c5a606836c18 100644
--- a/toolchain/lower/testdata/function/call/var_param.carbon
+++ b/toolchain/lower/testdata/function/call/var_param.carbon
@@ -31,3 +31,11 @@ fn Main() {
 // CHECK:STDOUT:   call void @DoNothing(i32 %.loc15)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "var_param.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/declaration/simple.carbon b/toolchain/lower/testdata/function/declaration/simple.carbon
index 50d8f01dbd7ba..8d87441bccd9e 100644
--- a/toolchain/lower/testdata/function/declaration/simple.carbon
+++ b/toolchain/lower/testdata/function/declaration/simple.carbon
@@ -22,3 +22,11 @@ fn G(n: i32) { F(n); }
 // CHECK:STDOUT:   call void @F(i32 %n)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "simple.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/definition/empty_struct.carbon b/toolchain/lower/testdata/function/definition/empty_struct.carbon
index 211dbf21a0e65..f2485ef74fee5 100644
--- a/toolchain/lower/testdata/function/definition/empty_struct.carbon
+++ b/toolchain/lower/testdata/function/definition/empty_struct.carbon
@@ -18,3 +18,11 @@ fn Echo(a: {}) {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "empty_struct.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/definition/params_one.carbon b/toolchain/lower/testdata/function/definition/params_one.carbon
index 7e181e7eb59f6..c5e6f8ff4eab4 100644
--- a/toolchain/lower/testdata/function/definition/params_one.carbon
+++ b/toolchain/lower/testdata/function/definition/params_one.carbon
@@ -17,3 +17,11 @@ fn Foo(a: i32) {}
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "params_one.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/definition/params_two.carbon b/toolchain/lower/testdata/function/definition/params_two.carbon
index 06952a0903317..37d197109cd9e 100644
--- a/toolchain/lower/testdata/function/definition/params_two.carbon
+++ b/toolchain/lower/testdata/function/definition/params_two.carbon
@@ -17,3 +17,11 @@ fn Foo(a: i32, b: i32) {}
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "params_two.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/definition/params_zero.carbon b/toolchain/lower/testdata/function/definition/params_zero.carbon
index 287fa72095339..226215750df41 100644
--- a/toolchain/lower/testdata/function/definition/params_zero.carbon
+++ b/toolchain/lower/testdata/function/definition/params_zero.carbon
@@ -17,3 +17,11 @@ fn Foo() {}
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "params_zero.carbon", directory: "")
diff --git a/toolchain/lower/testdata/function/generic/type_param.carbon b/toolchain/lower/testdata/function/generic/type_param.carbon
index d827a3eb7a34c..546f1ac0dca50 100644
--- a/toolchain/lower/testdata/function/generic/type_param.carbon
+++ b/toolchain/lower/testdata/function/generic/type_param.carbon
@@ -15,3 +15,11 @@ fn F(T:! type) {
 
 // CHECK:STDOUT: ; ModuleID = 'type_param.carbon'
 // CHECK:STDOUT: source_filename = "type_param.carbon"
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "type_param.carbon", directory: "")
diff --git a/toolchain/lower/testdata/global/class_obj.carbon b/toolchain/lower/testdata/global/class_obj.carbon
index f29ffdb413548..c3d8b99a946a6 100644
--- a/toolchain/lower/testdata/global/class_obj.carbon
+++ b/toolchain/lower/testdata/global/class_obj.carbon
@@ -28,3 +28,11 @@ var a: A = {};
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "class_obj.carbon", directory: "")
diff --git a/toolchain/lower/testdata/global/class_with_fun.carbon b/toolchain/lower/testdata/global/class_with_fun.carbon
index 290324de43f2b..e8b1a82317ffe 100644
--- a/toolchain/lower/testdata/global/class_with_fun.carbon
+++ b/toolchain/lower/testdata/global/class_with_fun.carbon
@@ -42,3 +42,11 @@ var a: A = {};
 // CHECK:STDOUT: uselistorder ptr @llvm.memcpy.p0.p0.i64, { 1, 0 }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "class_with_fun.carbon", directory: "")
diff --git a/toolchain/lower/testdata/global/decl.carbon b/toolchain/lower/testdata/global/decl.carbon
index ba68e1b4973ed..be0ac140c9857 100644
--- a/toolchain/lower/testdata/global/decl.carbon
+++ b/toolchain/lower/testdata/global/decl.carbon
@@ -13,3 +13,11 @@ var a: i32;
 // CHECK:STDOUT: source_filename = "decl.carbon"
 // CHECK:STDOUT:
 // CHECK:STDOUT: @a = internal global i32
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "decl.carbon", directory: "")
diff --git a/toolchain/lower/testdata/global/simple_init.carbon b/toolchain/lower/testdata/global/simple_init.carbon
index b1f376eb327ad..6425273ea606a 100644
--- a/toolchain/lower/testdata/global/simple_init.carbon
+++ b/toolchain/lower/testdata/global/simple_init.carbon
@@ -23,3 +23,11 @@ var a: i32 = 0;
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder i32 0, { 1, 0 }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "simple_init.carbon", directory: "")
diff --git a/toolchain/lower/testdata/global/simple_with_fun.carbon b/toolchain/lower/testdata/global/simple_with_fun.carbon
index 164c5bbd27963..5e988e81a9346 100644
--- a/toolchain/lower/testdata/global/simple_with_fun.carbon
+++ b/toolchain/lower/testdata/global/simple_with_fun.carbon
@@ -34,3 +34,11 @@ var a: i32 = test_a();
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder i32 0, { 1, 0 }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "simple_with_fun.carbon", directory: "")
diff --git a/toolchain/lower/testdata/if/else.carbon b/toolchain/lower/testdata/if/else.carbon
index 4903751e373cc..a32ef445aa2f5 100644
--- a/toolchain/lower/testdata/if/else.carbon
+++ b/toolchain/lower/testdata/if/else.carbon
@@ -55,3 +55,11 @@ fn If(b: bool) {
 // CHECK:STDOUT:   call void @H()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "else.carbon", directory: "")
diff --git a/toolchain/lower/testdata/if/no_else.carbon b/toolchain/lower/testdata/if/no_else.carbon
index 80759aa4aabcc..6e980c9895272 100644
--- a/toolchain/lower/testdata/if/no_else.carbon
+++ b/toolchain/lower/testdata/if/no_else.carbon
@@ -43,3 +43,11 @@ fn If(b: bool) {
 // CHECK:STDOUT:   call void @G()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "no_else.carbon", directory: "")
diff --git a/toolchain/lower/testdata/if_expr/basic.carbon b/toolchain/lower/testdata/if_expr/basic.carbon
index 360828e847464..635525b59f8dd 100644
--- a/toolchain/lower/testdata/if_expr/basic.carbon
+++ b/toolchain/lower/testdata/if_expr/basic.carbon
@@ -44,3 +44,11 @@ fn Select(b: bool) -> i32 {
 // CHECK:STDOUT:   %0 = phi i32 [ %F.call, %if.expr.then ], [ %G.call, %if.expr.else ]
 // CHECK:STDOUT:   ret i32 %0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "basic.carbon", directory: "")
diff --git a/toolchain/lower/testdata/if_expr/empty_block.carbon b/toolchain/lower/testdata/if_expr/empty_block.carbon
index 28addd0bd21c4..332990f17452e 100644
--- a/toolchain/lower/testdata/if_expr/empty_block.carbon
+++ b/toolchain/lower/testdata/if_expr/empty_block.carbon
@@ -49,3 +49,11 @@ fn Select(b: bool, c: bool, d: bool) -> i32 {
 // CHECK:STDOUT:   %2 = phi i32 [ %0, %if.expr.result.loc12_20 ], [ %1, %if.expr.result.loc12_44 ]
 // CHECK:STDOUT:   ret i32 %2
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "empty_block.carbon", directory: "")
diff --git a/toolchain/lower/testdata/impl/assoc_fn_alias.carbon b/toolchain/lower/testdata/impl/assoc_fn_alias.carbon
index cc807b9da153b..a1579b954f195 100644
--- a/toolchain/lower/testdata/impl/assoc_fn_alias.carbon
+++ b/toolchain/lower/testdata/impl/assoc_fn_alias.carbon
@@ -42,3 +42,11 @@ fn Call(a: A) -> i32 {
 // CHECK:STDOUT:   %F.call = call i32 @F(ptr %a)
 // CHECK:STDOUT:   ret i32 %F.call
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "assoc_fn_alias.carbon", directory: "")
diff --git a/toolchain/lower/testdata/impl/extend_impl.carbon b/toolchain/lower/testdata/impl/extend_impl.carbon
index 7bf5d812987b3..c0592d69f686c 100644
--- a/toolchain/lower/testdata/impl/extend_impl.carbon
+++ b/toolchain/lower/testdata/impl/extend_impl.carbon
@@ -47,3 +47,11 @@ fn InstanceAccess(a: A) -> i32 {
 // CHECK:STDOUT:   %F.call = call i32 @F()
 // CHECK:STDOUT:   ret i32 %F.call
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "extend_impl.carbon", directory: "")
diff --git a/toolchain/lower/testdata/impl/impl.carbon b/toolchain/lower/testdata/impl/impl.carbon
index 0a1d2c72897cb..116106279e103 100644
--- a/toolchain/lower/testdata/impl/impl.carbon
+++ b/toolchain/lower/testdata/impl/impl.carbon
@@ -41,3 +41,11 @@ fn Call(a: A) -> i32 {
 // CHECK:STDOUT:   %F.call = call i32 @F(ptr %a)
 // CHECK:STDOUT:   ret i32 %F.call
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "impl.carbon", directory: "")
diff --git a/toolchain/lower/testdata/impl/instance_method.carbon b/toolchain/lower/testdata/impl/instance_method.carbon
index fe5edb73657cf..88000ebe8e454 100644
--- a/toolchain/lower/testdata/impl/instance_method.carbon
+++ b/toolchain/lower/testdata/impl/instance_method.carbon
@@ -39,3 +39,11 @@ fn Call(a: A*) -> A* {
 // CHECK:STDOUT:   %Get.call = call ptr @Get(ptr %a)
 // CHECK:STDOUT:   ret ptr %Get.call
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "instance_method.carbon", directory: "")
diff --git a/toolchain/lower/testdata/index/array_element_access.carbon b/toolchain/lower/testdata/index/array_element_access.carbon
index 24952276f495d..570f6965892bf 100644
--- a/toolchain/lower/testdata/index/array_element_access.carbon
+++ b/toolchain/lower/testdata/index/array_element_access.carbon
@@ -76,3 +76,11 @@ fn Run() {
 // CHECK:STDOUT: uselistorder ptr @llvm.memcpy.p0.p0.i64, { 1, 0 }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "array_element_access.carbon", directory: "")
diff --git a/toolchain/lower/testdata/interface/assoc.carbon b/toolchain/lower/testdata/interface/assoc.carbon
index 9c228855224d4..5bed23d53e93c 100644
--- a/toolchain/lower/testdata/interface/assoc.carbon
+++ b/toolchain/lower/testdata/interface/assoc.carbon
@@ -21,3 +21,11 @@ fn F() { I.Assoc; }
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "assoc.carbon", directory: "")
diff --git a/toolchain/lower/testdata/interface/basic.carbon b/toolchain/lower/testdata/interface/basic.carbon
index dd624d6bba277..ac9a3fccb3eef 100644
--- a/toolchain/lower/testdata/interface/basic.carbon
+++ b/toolchain/lower/testdata/interface/basic.carbon
@@ -33,3 +33,11 @@ fn G(T: J) {}
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "basic.carbon", directory: "")
diff --git a/toolchain/lower/testdata/let/local.carbon b/toolchain/lower/testdata/let/local.carbon
index edf5eb251d28c..fbd996d852bed 100644
--- a/toolchain/lower/testdata/let/local.carbon
+++ b/toolchain/lower/testdata/let/local.carbon
@@ -21,3 +21,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i32 1
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "local.carbon", directory: "")
diff --git a/toolchain/lower/testdata/let/tuple.carbon b/toolchain/lower/testdata/let/tuple.carbon
index 7215f3f22db5c..8bcf83b2e6392 100644
--- a/toolchain/lower/testdata/let/tuple.carbon
+++ b/toolchain/lower/testdata/let/tuple.carbon
@@ -73,3 +73,11 @@ fn F() -> i32 {
 // CHECK:STDOUT: uselistorder ptr @llvm.memcpy.p0.p0.i64, { 1, 0 }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "tuple.carbon", directory: "")
diff --git a/toolchain/lower/testdata/namespace/function.carbon b/toolchain/lower/testdata/namespace/function.carbon
index 275c8c689eadd..f022c188de3d7 100644
--- a/toolchain/lower/testdata/namespace/function.carbon
+++ b/toolchain/lower/testdata/namespace/function.carbon
@@ -39,3 +39,11 @@ fn Bar() {
 // CHECK:STDOUT:   call void @Baz.1()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "function.carbon", directory: "")
diff --git a/toolchain/lower/testdata/namespace/nested.carbon b/toolchain/lower/testdata/namespace/nested.carbon
index 072d7d36aa688..198ef5e13fd93 100644
--- a/toolchain/lower/testdata/namespace/nested.carbon
+++ b/toolchain/lower/testdata/namespace/nested.carbon
@@ -31,3 +31,11 @@ fn Foo.Bar.Baz() {
 // CHECK:STDOUT:   call void @Wiz()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "nested.carbon", directory: "")
diff --git a/toolchain/lower/testdata/operators/and.carbon b/toolchain/lower/testdata/operators/and.carbon
index babe6a123bb17..18de3b877cf00 100644
--- a/toolchain/lower/testdata/operators/and.carbon
+++ b/toolchain/lower/testdata/operators/and.carbon
@@ -41,3 +41,11 @@ fn And() -> bool {
 // CHECK:STDOUT:   %0 = phi i1 [ false, %entry ], [ %G.call, %and.rhs ]
 // CHECK:STDOUT:   ret i1 %0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "and.carbon", directory: "")
diff --git a/toolchain/lower/testdata/operators/and_empty_block.carbon b/toolchain/lower/testdata/operators/and_empty_block.carbon
index 6393f4c750b00..f8a2aeaebb209 100644
--- a/toolchain/lower/testdata/operators/and_empty_block.carbon
+++ b/toolchain/lower/testdata/operators/and_empty_block.carbon
@@ -28,3 +28,11 @@ fn And(b: bool, c: bool) -> bool {
 // CHECK:STDOUT:   %0 = phi i1 [ false, %entry ], [ %c, %and.rhs ]
 // CHECK:STDOUT:   ret i1 %0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "and_empty_block.carbon", directory: "")
diff --git a/toolchain/lower/testdata/operators/assignment.carbon b/toolchain/lower/testdata/operators/assignment.carbon
index 74fbe01f5af46..7bfe57893041b 100644
--- a/toolchain/lower/testdata/operators/assignment.carbon
+++ b/toolchain/lower/testdata/operators/assignment.carbon
@@ -36,3 +36,11 @@ fn Main() {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "assignment.carbon", directory: "")
diff --git a/toolchain/lower/testdata/operators/not.carbon b/toolchain/lower/testdata/operators/not.carbon
index bbd19c3c6b4ec..e94d24701f51f 100644
--- a/toolchain/lower/testdata/operators/not.carbon
+++ b/toolchain/lower/testdata/operators/not.carbon
@@ -20,3 +20,11 @@ fn Not(b: bool) -> bool {
 // CHECK:STDOUT:   %.loc12 = xor i1 %b, true
 // CHECK:STDOUT:   ret i1 %.loc12
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "not.carbon", directory: "")
diff --git a/toolchain/lower/testdata/operators/or.carbon b/toolchain/lower/testdata/operators/or.carbon
index 0d28c26cc60fe..a045daa2d8375 100644
--- a/toolchain/lower/testdata/operators/or.carbon
+++ b/toolchain/lower/testdata/operators/or.carbon
@@ -42,3 +42,11 @@ fn Or() -> bool {
 // CHECK:STDOUT:   %0 = phi i1 [ true, %entry ], [ %G.call, %or.rhs ]
 // CHECK:STDOUT:   ret i1 %0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "or.carbon", directory: "")
diff --git a/toolchain/lower/testdata/operators/or_empty_block.carbon b/toolchain/lower/testdata/operators/or_empty_block.carbon
index cc9ec1bda6ba2..ee50df2e569d3 100644
--- a/toolchain/lower/testdata/operators/or_empty_block.carbon
+++ b/toolchain/lower/testdata/operators/or_empty_block.carbon
@@ -29,3 +29,11 @@ fn Or(b: bool, c: bool) -> bool {
 // CHECK:STDOUT:   %0 = phi i1 [ true, %entry ], [ %c, %or.rhs ]
 // CHECK:STDOUT:   ret i1 %0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "or_empty_block.carbon", directory: "")
diff --git a/toolchain/lower/testdata/operators/overloaded.carbon b/toolchain/lower/testdata/operators/overloaded.carbon
index 835b4d599a12a..cc3a82d804e86 100644
--- a/toolchain/lower/testdata/operators/overloaded.carbon
+++ b/toolchain/lower/testdata/operators/overloaded.carbon
@@ -90,3 +90,11 @@ fn Calculate(a: Number, b: Number) -> Number {
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder i1 true, { 2, 0, 1, 3, 4 }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "overloaded.carbon", directory: "")
diff --git a/toolchain/lower/testdata/packages/cross_package_call.carbon b/toolchain/lower/testdata/packages/cross_package_call.carbon
index 6c2b4e76142e8..11960438b016f 100644
--- a/toolchain/lower/testdata/packages/cross_package_call.carbon
+++ b/toolchain/lower/testdata/packages/cross_package_call.carbon
@@ -27,6 +27,14 @@ fn G() { A.F(); }
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "a.carbon", directory: "")
 // CHECK:STDOUT: ; ModuleID = 'b.carbon'
 // CHECK:STDOUT: source_filename = "b.carbon"
 // CHECK:STDOUT:
@@ -37,3 +45,11 @@ fn G() { A.F(); }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: declare void @F()
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "b.carbon", directory: "")
diff --git a/toolchain/lower/testdata/pointer/address_of_field.carbon b/toolchain/lower/testdata/pointer/address_of_field.carbon
index 9db04baf6e6f5..17152c3d8ba7d 100644
--- a/toolchain/lower/testdata/pointer/address_of_field.carbon
+++ b/toolchain/lower/testdata/pointer/address_of_field.carbon
@@ -37,3 +37,11 @@ fn F() {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "address_of_field.carbon", directory: "")
diff --git a/toolchain/lower/testdata/pointer/address_of_unused.carbon b/toolchain/lower/testdata/pointer/address_of_unused.carbon
index 9bd6024c6bf04..d639108d95097 100644
--- a/toolchain/lower/testdata/pointer/address_of_unused.carbon
+++ b/toolchain/lower/testdata/pointer/address_of_unused.carbon
@@ -22,3 +22,11 @@ fn F() {
 // CHECK:STDOUT:   store i32 0, ptr %n.var, align 4
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "address_of_unused.carbon", directory: "")
diff --git a/toolchain/lower/testdata/pointer/basic.carbon b/toolchain/lower/testdata/pointer/basic.carbon
index 8d94914bdd408..194dd15d82192 100644
--- a/toolchain/lower/testdata/pointer/basic.carbon
+++ b/toolchain/lower/testdata/pointer/basic.carbon
@@ -33,3 +33,11 @@ fn F() -> i32 {
 // CHECK:STDOUT:   %G.call = call i32 @G(ptr %n.var)
 // CHECK:STDOUT:   ret i32 %G.call
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "basic.carbon", directory: "")
diff --git a/toolchain/lower/testdata/pointer/pointer_to_pointer.carbon b/toolchain/lower/testdata/pointer/pointer_to_pointer.carbon
index a9b2ed1f4aab6..50994234dcf0a 100644
--- a/toolchain/lower/testdata/pointer/pointer_to_pointer.carbon
+++ b/toolchain/lower/testdata/pointer/pointer_to_pointer.carbon
@@ -32,3 +32,11 @@ fn F(p: i32**) -> i32 {
 // CHECK:STDOUT:   %.loc15_10.2 = load i32, ptr %.loc15_11.2, align 4
 // CHECK:STDOUT:   ret i32 %.loc15_10.2
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "pointer_to_pointer.carbon", directory: "")
diff --git a/toolchain/lower/testdata/return/code_after_return.carbon b/toolchain/lower/testdata/return/code_after_return.carbon
index 5ee26d112ee71..84a23dc32c789 100644
--- a/toolchain/lower/testdata/return/code_after_return.carbon
+++ b/toolchain/lower/testdata/return/code_after_return.carbon
@@ -27,3 +27,11 @@ fn Main() {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "code_after_return.carbon", directory: "")
diff --git a/toolchain/lower/testdata/return/no_value.carbon b/toolchain/lower/testdata/return/no_value.carbon
index 3be486fb12410..d5a068b8b2fc8 100644
--- a/toolchain/lower/testdata/return/no_value.carbon
+++ b/toolchain/lower/testdata/return/no_value.carbon
@@ -19,3 +19,11 @@ fn Main() {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "no_value.carbon", directory: "")
diff --git a/toolchain/lower/testdata/return/return_var.carbon b/toolchain/lower/testdata/return/return_var.carbon
index a41c83f41d063..9fe416aadd6a9 100644
--- a/toolchain/lower/testdata/return/return_var.carbon
+++ b/toolchain/lower/testdata/return/return_var.carbon
@@ -29,3 +29,11 @@ fn Make() -> C {
 // CHECK:STDOUT:   store ptr %return, ptr %.loc18_30.4.next, align 8
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "return_var.carbon", directory: "")
diff --git a/toolchain/lower/testdata/return/return_var_byval.carbon b/toolchain/lower/testdata/return/return_var_byval.carbon
index 0214d853728a2..97e9e857d7b72 100644
--- a/toolchain/lower/testdata/return/return_var_byval.carbon
+++ b/toolchain/lower/testdata/return/return_var_byval.carbon
@@ -23,3 +23,11 @@ fn Main() -> i32 {
 // CHECK:STDOUT:   %.loc12_16 = load i32, ptr %x.var, align 4
 // CHECK:STDOUT:   ret i32 %.loc12_16
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "return_var_byval.carbon", directory: "")
diff --git a/toolchain/lower/testdata/return/value.carbon b/toolchain/lower/testdata/return/value.carbon
index 05b9c7cdebef7..66eded6f5fbdd 100644
--- a/toolchain/lower/testdata/return/value.carbon
+++ b/toolchain/lower/testdata/return/value.carbon
@@ -19,3 +19,11 @@ fn Main() -> i32 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i32 0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "value.carbon", directory: "")
diff --git a/toolchain/lower/testdata/return/var.carbon b/toolchain/lower/testdata/return/var.carbon
index 86f2e560904d7..dfbe465a4134c 100644
--- a/toolchain/lower/testdata/return/var.carbon
+++ b/toolchain/lower/testdata/return/var.carbon
@@ -23,3 +23,11 @@ fn Main() -> i32 {
 // CHECK:STDOUT:   %.loc13 = load i32, ptr %x.var, align 4
 // CHECK:STDOUT:   ret i32 %.loc13
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "var.carbon", directory: "")
diff --git a/toolchain/lower/testdata/struct/empty.carbon b/toolchain/lower/testdata/struct/empty.carbon
index f7364fd7fead4..b85518f3367e5 100644
--- a/toolchain/lower/testdata/struct/empty.carbon
+++ b/toolchain/lower/testdata/struct/empty.carbon
@@ -23,3 +23,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT:   %y.var = alloca {}, align 8
 // CHECK:STDOUT:   ret i32 0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "empty.carbon", directory: "")
diff --git a/toolchain/lower/testdata/struct/member_access.carbon b/toolchain/lower/testdata/struct/member_access.carbon
index f01d2ad3fba09..81e0f2304a128 100644
--- a/toolchain/lower/testdata/struct/member_access.carbon
+++ b/toolchain/lower/testdata/struct/member_access.carbon
@@ -40,3 +40,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "member_access.carbon", directory: "")
diff --git a/toolchain/lower/testdata/struct/nested_struct.carbon b/toolchain/lower/testdata/struct/nested_struct.carbon
index e5b49994a13e4..6e93fd79d5dbf 100644
--- a/toolchain/lower/testdata/struct/nested_struct.carbon
+++ b/toolchain/lower/testdata/struct/nested_struct.carbon
@@ -20,3 +20,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i32 0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "nested_struct.carbon", directory: "")
diff --git a/toolchain/lower/testdata/struct/nested_struct_in_place.carbon b/toolchain/lower/testdata/struct/nested_struct_in_place.carbon
index 94d96d565eb31..549fda3591084 100644
--- a/toolchain/lower/testdata/struct/nested_struct_in_place.carbon
+++ b/toolchain/lower/testdata/struct/nested_struct_in_place.carbon
@@ -28,3 +28,11 @@ fn G() {
 // CHECK:STDOUT:   call void @F(ptr %.loc14_74.2.b)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "nested_struct_in_place.carbon", directory: "")
diff --git a/toolchain/lower/testdata/struct/one_entry.carbon b/toolchain/lower/testdata/struct/one_entry.carbon
index a3857e8550ad8..657665963d9a3 100644
--- a/toolchain/lower/testdata/struct/one_entry.carbon
+++ b/toolchain/lower/testdata/struct/one_entry.carbon
@@ -28,3 +28,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT:   store { i32 } %.loc13_22.3.struct.init, ptr %y.var, align 4
 // CHECK:STDOUT:   ret i32 0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "one_entry.carbon", directory: "")
diff --git a/toolchain/lower/testdata/struct/two_entries.carbon b/toolchain/lower/testdata/struct/two_entries.carbon
index 0c74c7cf9e58b..9e3c9e146d26b 100644
--- a/toolchain/lower/testdata/struct/two_entries.carbon
+++ b/toolchain/lower/testdata/struct/two_entries.carbon
@@ -41,3 +41,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "two_entries.carbon", directory: "")
diff --git a/toolchain/lower/testdata/tuple/access/element_access.carbon b/toolchain/lower/testdata/tuple/access/element_access.carbon
index 25a1ab4fc9ead..84ef16fd5de13 100644
--- a/toolchain/lower/testdata/tuple/access/element_access.carbon
+++ b/toolchain/lower/testdata/tuple/access/element_access.carbon
@@ -42,3 +42,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "element_access.carbon", directory: "")
diff --git a/toolchain/lower/testdata/tuple/access/return_value_access.carbon b/toolchain/lower/testdata/tuple/access/return_value_access.carbon
index 1521d084e8bff..775ce1e8cea0b 100644
--- a/toolchain/lower/testdata/tuple/access/return_value_access.carbon
+++ b/toolchain/lower/testdata/tuple/access/return_value_access.carbon
@@ -42,3 +42,11 @@ fn Run() {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "return_value_access.carbon", directory: "")
diff --git a/toolchain/lower/testdata/tuple/empty.carbon b/toolchain/lower/testdata/tuple/empty.carbon
index 5b7d4801a5ca4..71c06b1c52105 100644
--- a/toolchain/lower/testdata/tuple/empty.carbon
+++ b/toolchain/lower/testdata/tuple/empty.carbon
@@ -23,3 +23,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT:   %y.var = alloca {}, align 8
 // CHECK:STDOUT:   ret i32 0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "empty.carbon", directory: "")
diff --git a/toolchain/lower/testdata/tuple/nested_tuple.carbon b/toolchain/lower/testdata/tuple/nested_tuple.carbon
index 3a5888e017d93..41e287e44a9af 100644
--- a/toolchain/lower/testdata/tuple/nested_tuple.carbon
+++ b/toolchain/lower/testdata/tuple/nested_tuple.carbon
@@ -20,3 +20,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i32 0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "nested_tuple.carbon", directory: "")
diff --git a/toolchain/lower/testdata/tuple/nested_tuple_in_place.carbon b/toolchain/lower/testdata/tuple/nested_tuple_in_place.carbon
index 5dc8fe1fa42fc..6437a64c1d63c 100644
--- a/toolchain/lower/testdata/tuple/nested_tuple_in_place.carbon
+++ b/toolchain/lower/testdata/tuple/nested_tuple_in_place.carbon
@@ -28,3 +28,11 @@ fn G() {
 // CHECK:STDOUT:   call void @F(ptr %.loc14_56.2.tuple.elem)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "nested_tuple_in_place.carbon", directory: "")
diff --git a/toolchain/lower/testdata/tuple/one_entry.carbon b/toolchain/lower/testdata/tuple/one_entry.carbon
index 83fa542655768..0da72917bb1fa 100644
--- a/toolchain/lower/testdata/tuple/one_entry.carbon
+++ b/toolchain/lower/testdata/tuple/one_entry.carbon
@@ -31,3 +31,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder i32 1, { 0, 2, 1 }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "one_entry.carbon", directory: "")
diff --git a/toolchain/lower/testdata/tuple/two_entries.carbon b/toolchain/lower/testdata/tuple/two_entries.carbon
index 3eb65db7a6bf2..ee339ca236c5d 100644
--- a/toolchain/lower/testdata/tuple/two_entries.carbon
+++ b/toolchain/lower/testdata/tuple/two_entries.carbon
@@ -41,3 +41,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "two_entries.carbon", directory: "")
diff --git a/toolchain/lower/testdata/tuple/value_formation.carbon b/toolchain/lower/testdata/tuple/value_formation.carbon
index 94138a454f7c1..27c3dc01147b0 100644
--- a/toolchain/lower/testdata/tuple/value_formation.carbon
+++ b/toolchain/lower/testdata/tuple/value_formation.carbon
@@ -59,3 +59,11 @@ fn F() {
 // CHECK:STDOUT:   call void @G(ptr %tuple.loc16_10)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "value_formation.carbon", directory: "")
diff --git a/toolchain/lower/testdata/tuple/value_forwarding.carbon b/toolchain/lower/testdata/tuple/value_forwarding.carbon
index 15dba88e41719..d35387e7025f0 100644
--- a/toolchain/lower/testdata/tuple/value_forwarding.carbon
+++ b/toolchain/lower/testdata/tuple/value_forwarding.carbon
@@ -29,3 +29,11 @@ fn F(a: (i32, i32, i32), b: (i32, i32, i32)) {
 // CHECK:STDOUT:   call void @G(ptr %tuple)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "value_forwarding.carbon", directory: "")
diff --git a/toolchain/lower/testdata/var/local.carbon b/toolchain/lower/testdata/var/local.carbon
index 8d34b2b29ed46..01a069d9a9fd8 100644
--- a/toolchain/lower/testdata/var/local.carbon
+++ b/toolchain/lower/testdata/var/local.carbon
@@ -23,3 +23,11 @@ fn Run() -> i32 {
 // CHECK:STDOUT:   %.loc13 = load i32, ptr %x.var, align 4
 // CHECK:STDOUT:   ret i32 %.loc13
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "local.carbon", directory: "")
diff --git a/toolchain/lower/testdata/while/break_continue.carbon b/toolchain/lower/testdata/while/break_continue.carbon
index 7dbeca8ef07f2..49403fc6baad1 100644
--- a/toolchain/lower/testdata/while/break_continue.carbon
+++ b/toolchain/lower/testdata/while/break_continue.carbon
@@ -59,3 +59,11 @@ fn While() {
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT:   uselistorder label %while.cond, { 1, 2, 0 }
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "break_continue.carbon", directory: "")
diff --git a/toolchain/lower/testdata/while/preheader.carbon b/toolchain/lower/testdata/while/preheader.carbon
index 5e19981371e4e..b131890e633d6 100644
--- a/toolchain/lower/testdata/while/preheader.carbon
+++ b/toolchain/lower/testdata/while/preheader.carbon
@@ -70,3 +70,11 @@ fn While() {
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT:   uselistorder label %while.cond.loc20, { 1, 0 }
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "preheader.carbon", directory: "")
diff --git a/toolchain/lower/testdata/while/unreachable_end.carbon b/toolchain/lower/testdata/while/unreachable_end.carbon
index d4d352efca5c8..5e2d1a71da38f 100644
--- a/toolchain/lower/testdata/while/unreachable_end.carbon
+++ b/toolchain/lower/testdata/while/unreachable_end.carbon
@@ -51,3 +51,11 @@ fn While() {
 // CHECK:STDOUT:   call void @H()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "unreachable_end.carbon", directory: "")
diff --git a/toolchain/lower/testdata/while/while.carbon b/toolchain/lower/testdata/while/while.carbon
index 763dea3f773d3..9a408935627ce 100644
--- a/toolchain/lower/testdata/while/while.carbon
+++ b/toolchain/lower/testdata/while/while.carbon
@@ -50,3 +50,11 @@ fn While() {
 // CHECK:STDOUT:   call void @H()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "while.carbon", directory: "")
diff --git a/toolchain/testing/file_test.cpp b/toolchain/testing/file_test.cpp
index fc2f119a01d96..9d554dd309bdc 100644
--- a/toolchain/testing/file_test.cpp
+++ b/toolchain/testing/file_test.cpp
@@ -70,6 +70,7 @@ class ToolchainFileTest : public FileTestBase {
       args.push_back("--dump-sem-ir");
     } else if (component_ == "lower") {
       args.push_back("--dump-llvm-ir");
+      args.push_back("--debug-info");
     } else {
       CARBON_FATAL() << "Unexpected test component " << component_ << ": "
                      << test_name();