Auto merge of #120370 - x17jiri:likely_unlikely_fix, r=saethlin

Likely unlikely fix

RFC 1131 ( https://github.com/rust-lang/rust/issues/26179 ) added likely/unlikely intrinsics, but they have been broken for a while: https://github.com/rust-lang/rust/issues/96276 , https://github.com/rust-lang/rust/issues/96275 , https://github.com/rust-lang/rust/issues/88767 . This PR tries to fix them.

Changes:
- added a new `cold_path()` intrinsic
- `likely()` and `unlikely()` changed to regular functions implemented using `cold_path()`

1 files changed, 4 insertions, 5 deletions

diff --git a/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs b/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
index 1e2e41b3122..b92885cc1a7 100644
--- a/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
@@ -453,11 +453,6 @@ fn codegen_regular_intrinsic_call<'tcx>(
             fx.bcx.ins().trap(TrapCode::user(2).unwrap());
             return Ok(());
         }
-        sym::likely | sym::unlikely => {
-            intrinsic_args!(fx, args => (a); intrinsic);
-
-            ret.write_cvalue(fx, a);
-        }
         sym::breakpoint => {
             intrinsic_args!(fx, args => (); intrinsic);
 
@@ -1267,6 +1262,10 @@ fn codegen_regular_intrinsic_call<'tcx>(
             );
         }
 
+        sym::cold_path => {
+            // This is a no-op. The intrinsic is just a hint to the optimizer.
+        }
+
         // Unimplemented intrinsics must have a fallback body. The fallback body is obtained
         // by converting the `InstanceKind::Intrinsic` to an `InstanceKind::Item`.
         _ => {