Auto merge of #132779 - klensy:pgo-cold, r=<try>

try ColdFuncOpt variants for PGO

r? `@ghost`

Author: bors

compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -712,15 +712,15 @@ extern "C" LLVMRustResult LLVMRustOptimize(
     PGOOpt = PGOOptions(PGOGenPath, "", "", "", FS, PGOOptions::IRInstr,
                         PGOOptions::NoCSAction,
 #if LLVM_VERSION_GE(19, 0)
-                        PGOOptions::ColdFuncOpt::Default,
+                        PGOOptions::ColdFuncOpt::MinSize,
 #endif
                         DebugInfoForProfiling);
   } else if (PGOUsePath) {
     assert(!PGOSampleUsePath);
     PGOOpt = PGOOptions(PGOUsePath, "", "", "", FS, PGOOptions::IRUse,
                         PGOOptions::NoCSAction,
 #if LLVM_VERSION_GE(19, 0)
-                        PGOOptions::ColdFuncOpt::Default,
+                        PGOOptions::ColdFuncOpt::MinSize,
 #endif
                         DebugInfoForProfiling);
   } else if (PGOSampleUsePath) {

src/bootstrap/src/core/build_steps/compile.rs

@@ -1112,13 +1112,15 @@ pub fn rustc_cargo(
             // Apparently necessary to avoid overflowing the counters during
             // a Cargo build profile
             cargo.rustflag("-Cllvm-args=-vp-counters-per-site=4");
+            cargo.rustflag("-Cllvm-args=-enable-pgo-force-function-attrs");
             true
         } else {
             false
         }
     } else if let Some(path) = &builder.config.rust_profile_use {
         if compiler.stage == 1 {
             cargo.rustflag(&format!("-Cprofile-use={path}"));
+            cargo.rustflag("-Cllvm-args=-enable-pgo-force-function-attrs");
             if builder.is_verbose() {
                 cargo.rustflag("-Cllvm-args=-pgo-warn-missing-function");
             }