[Pipelines] Don't run ForceFunctionAttrs post-link

[nikic]

Summary

This is effectively a debugging pass to adjust function attributes. I don't think it makes sense to run it in the post-link pipeline.

[aeubanks]

clang test needs updating (I wonder if it's redundant with any other test)

llvm/lib/Passes/PassBuilderPipelines.cpp

if (Level == OptimizationLevel::O0) {
     // Drop available_externally and unreferenced globals. This is necessary
     // with ThinLTO in order to avoid leaving undefined references to dead
     // globals in the object file.
     MPM.addPass(EliminateAvailableExternallyPass());
     MPM.addPass(GlobalDCEPass());
     return MPM;
   }
 
-  // Force any function attributes we want the rest of the pipeline to observe.
-  MPM.addPass(ForceFunctionAttrsPass());
-
   // Add the core simplification pipeline.
   MPM.addPass(buildModuleSimplificationPipeline(
       Level, ThinOrFullLTOPhase::ThinLTOPostLink));
 
   // Now add the optimization pipeline.
   MPM.addPass(buildModuleOptimizationPipeline(
       Level, ThinOrFullLTOPhase::ThinLTOPostLink));
 
PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
 
   // Try to run OpenMP optimizations, quick no-op if no OpenMP metadata present.
   MPM.addPass(OpenMPOptPass(ThinOrFullLTOPhase::FullLTOPostLink));
 
   // Remove unused virtual tables to improve the quality of code generated by
   // whole-program devirtualization and bitset lowering.
   MPM.addPass(GlobalDCEPass());
 
-  // Force any function attributes we want the rest of the pipeline to observe.
-  MPM.addPass(ForceFunctionAttrsPass());
-
   // Do basic inference of function attributes from known properties of system
   // libraries and other oracles.
   MPM.addPass(InferFunctionAttrsPass());
 
   if (Level.getSpeedupLevel() > 1) {
     MPM.addPass(createModuleToFunctionPassAdaptor(
         CallSiteSplittingPass(), PTO.EagerlyInvalidateAnalyses));
 

llvm/test/Other/new-pm-lto-defaults.ll

 ; RUN: opt -disable-verify -verify-analysis-invalidation=0 -eagerly-invalidate-analyses=0 -debug-pass-manager \
 ; RUN:     -passes='lto<O3>' -S  %s -passes-ep-peephole='no-op-function' 2>&1 \
 ; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-O3,CHECK-O23,CHECK-O23SZ,CHECK-EP-Peephole
 
 ; CHECK-EP: Running pass: NoOpModulePass
 ; CHECK-O: Running pass: CrossDSOCFIPass
 ; CHECK-O-NEXT: Running pass: OpenMPOptPass
 ; CHECK-O-NEXT: Running pass: GlobalDCEPass
-; CHECK-O-NEXT: Running pass: ForceFunctionAttrsPass
 ; CHECK-O-NEXT: Running pass: InferFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*}}Module
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O23SZ-NEXT: Running pass: CallSiteSplittingPass on foo
 ; CHECK-O23SZ-NEXT: Running analysis: TargetLibraryAnalysis on foo
 ; CHECK-O23SZ-NEXT: Running analysis: TargetIRAnalysis on foo
 ; CHECK-O23SZ-NEXT: Running analysis: DominatorTreeAnalysis on foo
 ; CHECK-O23SZ-NEXT: PGOIndirectCallPromotion

llvm/test/Other/new-pm-thinlto-postlink-defaults.ll

 ; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-NO-FUNC-SPEC,CHECK-O23SZ,CHECK-POSTLINK-O,%llvmcheckext
 ; RUN: opt -disable-verify -verify-analysis-invalidation=0 -eagerly-invalidate-analyses=0 -debug-pass-manager -debug-info-for-profiling \
 ; RUN:     -passes='thinlto<O2>' -S  %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-FUNC-SPEC,CHECK-O2,CHECK-O23SZ,CHECK-POSTLINK-O,%llvmcheckext,CHECK-POSTLINK-O2
 
 ; Suppress FileCheck --allow-unused-prefixes=false diagnostics.
 ; CHECK-NOEXT: {{^}}
 
-; CHECK-O: Running pass: ForceFunctionAttrsPass
-; CHECK-EP-PIPELINE-START-NEXT: Running pass: NoOpModulePass
-; CHECK-DIS-NEXT: Running analysis: InnerAnalysisManagerProxy
+; CHECK-EP-PIPELINE-START: Running pass: NoOpModulePass
+; CHECK-DIS: Running analysis: InnerAnalysisManagerProxy
 ; CHECK-DIS-NEXT: Running pass: AddDiscriminatorsPass
-; CHECK-POSTLINK-O-NEXT: Running pass: PGOIndirectCallPromotion
+; CHECK-POSTLINK-O: Running pass: PGOIndirectCallPromotion
 ; CHECK-POSTLINK-O-NEXT: Running analysis: ProfileSummaryAnalysis
 ; CHECK-POSTLINK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
 ; CHECK-POSTLINK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running pass: InferFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O-NEXT: Running pass: CoroEarlyPass
 ; CHECK-O-NEXT: Running pass: LowerExpectIntrinsicPass
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass

llvm/test/Other/new-pm-thinlto-postlink-pgo-defaults.ll

 ; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-OSZ,CHECK-O23SZ,%llvmcheckext
 ; RUN: opt -disable-verify -verify-analysis-invalidation=0 -eagerly-invalidate-analyses=0 -debug-pass-manager -debug-info-for-profiling \
 ; RUN:     -passes='thinlto<O2>' -S  %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-O123,CHECK-O2,CHECK-O23SZ,%llvmcheckext
 
 ; Suppress FileCheck --allow-unused-prefixes=false diagnostics.
 ; CHECK-NOEXT: {{^}}
 
-; CHECK-O: Running pass: ForceFunctionAttrsPass
-; CHECK-EP-PIPELINE-START-NEXT: Running pass: NoOpModulePass
-; CHECK-O-NEXT: Running pass: PGOIndirectCallPromotion
+; CHECK-EP-PIPELINE-START: Running pass: NoOpModulePass
+; CHECK-O: Running pass: PGOIndirectCallPromotion
 ; CHECK-O-NEXT: Running analysis: ProfileSummaryAnalysis
 ; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
 ; CHECK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running pass: InferFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O-NEXT: Running pass: CoroEarlyPass
 ; CHECK-O-NEXT: Running pass: LowerExpectIntrinsicPass
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass

llvm/test/Other/new-pm-thinlto-postlink-samplepgo-defaults.ll

 ; RUN: opt -disable-verify -verify-analysis-invalidation=0 -eagerly-invalidate-analyses=0 -debug-pass-manager -debug-info-for-profiling \
 ; RUN:     -pgo-kind=pgo-sample-use-pipeline -profile-file='%S/Inputs/new-pm-thinlto-samplepgo-defaults.prof' \
 ; RUN:     -passes='thinlto<O2>' -S  %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-O123,CHECK-O2,CHECK-O23SZ,%llvmcheckext
 
 ; Suppress FileCheck --allow-unused-prefixes=false diagnostics.
 ; CHECK-NOEXT: {{^}}
 
-; CHECK-O: Running pass: ForceFunctionAttrsPass
-; CHECK-EP-PIPELINE-START-NEXT: Running pass: NoOpModulePass
-; CHECK-O-NEXT: Running pass: InferFunctionAttrsPass
+; CHECK-EP-PIPELINE-START: Running pass: NoOpModulePass
+; CHECK-O: Running pass: InferFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O-NEXT: Running pass: CoroEarlyPass
 ; CHECK-O-NEXT: Running pass: LowerExpectIntrinsicPass
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
 ; CHECK-O-NEXT: Running analysis: TargetIRAnalysis
 ; CHECK-O-NEXT: Running analysis: AssumptionAnalysis
 ; CHECK-O-NEXT: Running pass: SROAPass