From 9aec5c5bcecad566a76fc7dbb819aa0e58a23671 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 9 Apr 2024 23:17:45 +0000
Subject: [PATCH 1/3] Add test for fn pointer duplication.

---
 tests/ui/mir/auxiliary/static_fnptr.rs | 10 ++++++++++
 tests/ui/mir/static_fnptr.rs           | 14 ++++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 tests/ui/mir/auxiliary/static_fnptr.rs
 create mode 100644 tests/ui/mir/static_fnptr.rs

diff --git a/tests/ui/mir/auxiliary/static_fnptr.rs b/tests/ui/mir/auxiliary/static_fnptr.rs
new file mode 100644
index 0000000000000..a48ee6c012105
--- /dev/null
+++ b/tests/ui/mir/auxiliary/static_fnptr.rs
@@ -0,0 +1,10 @@
+//@ compile-flags:-O
+
+fn foo() {}
+
+pub static ADDR: fn() = foo;
+
+#[inline(always)]
+pub fn bar(x: fn()) -> bool {
+    x == ADDR
+}
diff --git a/tests/ui/mir/static_fnptr.rs b/tests/ui/mir/static_fnptr.rs
new file mode 100644
index 0000000000000..571dcf4463e12
--- /dev/null
+++ b/tests/ui/mir/static_fnptr.rs
@@ -0,0 +1,14 @@
+//@ run-pass
+//@ compile-flags:-Cno-prepopulate-passes -Copt-level=0
+//@ aux-build:static_fnptr.rs
+
+extern crate static_fnptr;
+use static_fnptr::{ADDR, bar};
+
+fn baz() -> bool {
+    bar(ADDR)
+}
+
+fn main() {
+    assert!(baz())
+}

From d223ba6233455544818e0998d3352de8e237c896 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Wed, 10 Apr 2024 10:15:26 +0000
Subject: [PATCH 2/3] Document test.

---
 tests/ui/mir/static_fnptr.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tests/ui/mir/static_fnptr.rs b/tests/ui/mir/static_fnptr.rs
index 571dcf4463e12..6b1ec021629b8 100644
--- a/tests/ui/mir/static_fnptr.rs
+++ b/tests/ui/mir/static_fnptr.rs
@@ -1,3 +1,10 @@
+//! Verify that we correctly handle fn pointer provenance in MIR optimizations.
+//! By asking to inline `static_fnptr::bar`, we have two copies of `static_fnptr::foo`, one in the
+//! auxiliary crate and one in the local crate CGU.
+//! `baz` must only consider the versions from upstream crate, and not try to compare with the
+//! address of the CGU-local copy.
+//! Related issue: #123670
+
 //@ run-pass
 //@ compile-flags:-Cno-prepopulate-passes -Copt-level=0
 //@ aux-build:static_fnptr.rs

From 4c779d75bff7c7c83f4955c3f448198f6dd3c1db Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Sat, 4 May 2024 19:27:27 +0000
Subject: [PATCH 3/3] Mark `foo` as explicitly inline.

---
 tests/ui/mir/auxiliary/static_fnptr.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/ui/mir/auxiliary/static_fnptr.rs b/tests/ui/mir/auxiliary/static_fnptr.rs
index a48ee6c012105..8c7347175f4b8 100644
--- a/tests/ui/mir/auxiliary/static_fnptr.rs
+++ b/tests/ui/mir/auxiliary/static_fnptr.rs
@@ -1,5 +1,6 @@
 //@ compile-flags:-O
 
+#[inline]
 fn foo() {}
 
 pub static ADDR: fn() = foo;