Rollup merge of rust-lang#125173 - scottmcm:never-checked, r=davidtwco

Remove `Rvalue::CheckedBinaryOp`

Zulip conversation: <https://rust-lang.zulipchat.com/#narrow/stream/189540-t-compiler.2Fwg-mir-opt/topic/intrinsics.20vs.20binop.2Funop/near/438729996>
cc `@RalfJung`

While it's a draft,
r? ghost

src/base.rs

@@ -609,14 +609,11 @@ fn codegen_stmt<'tcx>(
                     let lhs = codegen_operand(fx, &lhs_rhs.0);
                     let rhs = codegen_operand(fx, &lhs_rhs.1);
 
-                    let res = crate::num::codegen_binop(fx, bin_op, lhs, rhs);
-                    lval.write_cvalue(fx, res);
-                }
-                Rvalue::CheckedBinaryOp(bin_op, ref lhs_rhs) => {
-                    let lhs = codegen_operand(fx, &lhs_rhs.0);
-                    let rhs = codegen_operand(fx, &lhs_rhs.1);
-
-                    let res = crate::num::codegen_checked_int_binop(fx, bin_op, lhs, rhs);
+                    let res = if let Some(bin_op) = bin_op.overflowing_to_wrapping() {
+                        crate::num::codegen_checked_int_binop(fx, bin_op, lhs, rhs)
+                    } else {
+                        crate::num::codegen_binop(fx, bin_op, lhs, rhs)
+                    };
                     lval.write_cvalue(fx, res);
                 }
                 Rvalue::UnaryOp(un_op, ref operand) => {

src/codegen_i128.rs

@@ -70,6 +70,7 @@ pub(crate) fn maybe_codegen<'tcx>(
         }
         BinOp::Lt | BinOp::Le | BinOp::Eq | BinOp::Ge | BinOp::Gt | BinOp::Ne | BinOp::Cmp => None,
         BinOp::Shl | BinOp::ShlUnchecked | BinOp::Shr | BinOp::ShrUnchecked => None,
+        BinOp::AddWithOverflow | BinOp::SubWithOverflow | BinOp::MulWithOverflow => unreachable!(),
     }
 }
 
@@ -132,6 +133,7 @@ pub(crate) fn maybe_codegen_checked<'tcx>(
             Some(out_place.to_cvalue(fx))
         }
         BinOp::AddUnchecked | BinOp::SubUnchecked | BinOp::MulUnchecked => unreachable!(),
+        BinOp::AddWithOverflow | BinOp::SubWithOverflow | BinOp::MulWithOverflow => unreachable!(),
         BinOp::Offset => unreachable!("offset should only be used on pointers, not 128bit ints"),
         BinOp::Div | BinOp::Rem => unreachable!(),
         BinOp::Cmp => unreachable!(),

src/num.rs

@@ -179,6 +179,9 @@ pub(crate) fn codegen_int_binop<'tcx>(
             }
         }
         BinOp::Offset => unreachable!("Offset is not an integer operation"),
+        BinOp::AddWithOverflow | BinOp::SubWithOverflow | BinOp::MulWithOverflow => {
+            unreachable!("Overflow binops handled by `codegen_checked_int_binop`")
+        }
         // Compare binops handles by `codegen_binop`.
         BinOp::Eq | BinOp::Ne | BinOp::Lt | BinOp::Le | BinOp::Gt | BinOp::Ge | BinOp::Cmp => {
             unreachable!("{:?}({:?}, {:?})", bin_op, in_lhs.layout().ty, in_rhs.layout().ty);