Author: dehao Date: Thu Jun 23 15:13:10 2016 New Revision: 273606 URL: http://llvm.org/viewvc/llvm-project?rev=273606&view=rev Log: Invoke simplifycfg and sroa before instcombine.
Summary: InstCombine needs to be performed after simplifycfg and sroa, otherwise it may make bad optimization decisions. Reviewers: davidxl, wmi, dnovillo Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D21568 Added: cfe/trunk/test/CodeGen/pgo-sample-preparation.c Modified: cfe/trunk/lib/CodeGen/BackendUtil.cpp cfe/trunk/test/CodeGen/pgo-sample.c Modified: cfe/trunk/lib/CodeGen/BackendUtil.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/BackendUtil.cpp?rev=273606&r1=273605&r2=273606&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/BackendUtil.cpp (original) +++ cfe/trunk/lib/CodeGen/BackendUtil.cpp Thu Jun 23 15:13:10 2016 @@ -178,8 +178,14 @@ static void addAddDiscriminatorsPass(con PM.add(createAddDiscriminatorsPass()); } -static void addInstructionCombiningPass(const PassManagerBuilder &Builder, - legacy::PassManagerBase &PM) { +static void addCleanupPassesForSampleProfiler( + const PassManagerBuilder &Builder, legacy::PassManagerBase &PM) { + // instcombine is needed before sample profile annotation because it converts + // certain function calls to be inlinable. simplifycfg and sroa are needed + // before instcombine for necessary preparation. E.g. load store is eliminated + // properly so that instcombine will not introduce unecessary liverange. + PM.add(createCFGSimplificationPass()); + PM.add(createSROAPass()); PM.add(createInstructionCombiningPass()); } @@ -492,7 +498,7 @@ void EmitAssemblyHelper::CreatePasses(Mo MPM->add(createPruneEHPass()); MPM->add(createSampleProfileLoaderPass(CodeGenOpts.SampleProfileFile)); PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible, - addInstructionCombiningPass); + addCleanupPassesForSampleProfiler); } PMBuilder.populateFunctionPassManager(*FPM); Added: cfe/trunk/test/CodeGen/pgo-sample-preparation.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/pgo-sample-preparation.c?rev=273606&view=auto ============================================================================== --- cfe/trunk/test/CodeGen/pgo-sample-preparation.c (added) +++ cfe/trunk/test/CodeGen/pgo-sample-preparation.c Thu Jun 23 15:13:10 2016 @@ -0,0 +1,16 @@ +// Test if PGO sample use preparation passes are executed correctly. +// +// Ensure that instcombine is executed after simplifycfg and sroa so that +// "a < 255" will not be converted to a * 256 < 255 * 256. +// RUN: %clang_cc1 -O2 -fprofile-sample-use=%S/Inputs/pgo-sample.prof %s -emit-llvm -o - 2>&1 | FileCheck %s + +void bar(int); +void foo(int x, int y, int z) { + int m; + for (m = 0; m < x ; m++) { + int a = (((y >> 8) & 0xff) * z) / 256; + bar(a < 255 ? a : 255); + } +} + +// CHECK-NOT: icmp slt i32 %mul, 65280 Modified: cfe/trunk/test/CodeGen/pgo-sample.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/pgo-sample.c?rev=273606&r1=273605&r2=273606&view=diff ============================================================================== --- cfe/trunk/test/CodeGen/pgo-sample.c (original) +++ cfe/trunk/test/CodeGen/pgo-sample.c Thu Jun 23 15:13:10 2016 @@ -2,5 +2,8 @@ // // Ensure Pass PGOInstrumentationGenPass is invoked. // RUN: %clang_cc1 -O2 -fprofile-sample-use=%S/Inputs/pgo-sample.prof %s -mllvm -debug-pass=Structure -emit-llvm -o - 2>&1 | FileCheck %s +// CHECK: Simplify the CFG +// CHECK: SROA +// CHECK: Combine redundant instructions // CHECK: Remove unused exception handling info // CHECK: Sample profile pass _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
