https://github.com/madhur13490 created https://github.com/llvm/llvm-project/pull/158844
This PR is a reapplication of https://github.com/llvm/llvm-project/pull/142686 >From 5c2490151089d6aca053236e7064859720949333 Mon Sep 17 00:00:00 2001 From: Madhur Amilkanthwar <madh...@nvidia.com> Date: Thu, 22 May 2025 13:50:38 +0000 Subject: [PATCH] [LoopFusion] Reapply "Introduce -fexperimental-loop-fusion to clang and flang" --- clang/include/clang/Basic/CodeGenOptions.def | 1 + clang/include/clang/Driver/Options.td | 4 ++++ clang/lib/CodeGen/BackendUtil.cpp | 2 ++ clang/lib/Driver/ToolChains/Clang.cpp | 2 ++ clang/lib/Driver/ToolChains/Flang.cpp | 3 +++ clang/lib/Frontend/CompilerInvocation.cpp | 5 +++++ clang/test/Driver/clang_f_opts.c | 9 +++++++++ flang/docs/ReleaseNotes.md | 2 ++ flang/include/flang/Frontend/CodeGenOptions.def | 1 + flang/lib/Frontend/CompilerInvocation.cpp | 3 +++ flang/lib/Frontend/FrontendActions.cpp | 1 + flang/test/Driver/loop-fuse.f90 | 17 +++++++++++++++++ llvm/include/llvm/Passes/PassBuilder.h | 3 +++ llvm/lib/Passes/PassBuilderPipelines.cpp | 9 ++++++++- llvm/tools/opt/NewPMDriver.cpp | 4 ++++ 15 files changed, 65 insertions(+), 1 deletion(-) create mode 100644 flang/test/Driver/loop-fuse.f90 diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def index fda0da99b60c0..872f73ebf3810 100644 --- a/clang/include/clang/Basic/CodeGenOptions.def +++ b/clang/include/clang/Basic/CodeGenOptions.def @@ -322,6 +322,7 @@ CODEGENOPT(TimeTrace , 1, 0, Benign) ///< Set when -ftime-trace is enabl VALUE_CODEGENOPT(TimeTraceGranularity, 32, 500, Benign) ///< Minimum time granularity (in microseconds), ///< traced by time profiler CODEGENOPT(InterchangeLoops , 1, 0, Benign) ///< Run loop-interchange. +CODEGENOPT(FuseLoops , 1, 0, Benign) ///< Run loop-fusion. CODEGENOPT(UnrollLoops , 1, 0, Benign) ///< Control whether loops are unrolled. CODEGENOPT(RerollLoops , 1, 0, Benign) ///< Control whether loops are rerolled. CODEGENOPT(NoUseJumpTables , 1, 0, Benign) ///< Set when -fno-jump-tables is enabled. diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index 54cc1e986b601..def7c09d58cfb 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -4304,6 +4304,10 @@ def floop_interchange : Flag<["-"], "floop-interchange">, Group<f_Group>, HelpText<"Enable the loop interchange pass">, Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>; def fno_loop_interchange: Flag<["-"], "fno-loop-interchange">, Group<f_Group>, HelpText<"Disable the loop interchange pass">, Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>; +defm experimental_loop_fusion + : OptInCC1FFlag<"experimental-loop-fusion", "Enable", "Disable", + "Enable the loop fusion pass", + [ClangOption, FlangOption, FC1Option]>; def funroll_loops : Flag<["-"], "funroll-loops">, Group<f_Group>, HelpText<"Turn on loop unroller">, Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>; def fno_unroll_loops : Flag<["-"], "fno-unroll-loops">, Group<f_Group>, diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp index 3f095c03397fd..8c99af2bdff83 100644 --- a/clang/lib/CodeGen/BackendUtil.cpp +++ b/clang/lib/CodeGen/BackendUtil.cpp @@ -896,6 +896,7 @@ void EmitAssemblyHelper::RunOptimizationPipeline( PipelineTuningOptions PTO; PTO.LoopUnrolling = CodeGenOpts.UnrollLoops; PTO.LoopInterchange = CodeGenOpts.InterchangeLoops; + PTO.LoopFusion = CodeGenOpts.FuseLoops; // For historical reasons, loop interleaving is set to mirror setting for loop // unrolling. PTO.LoopInterleaving = CodeGenOpts.UnrollLoops; @@ -1331,6 +1332,7 @@ runThinLTOBackend(CompilerInstance &CI, ModuleSummaryIndex *CombinedIndex, Conf.SampleProfile = std::move(SampleProfile); Conf.PTO.LoopUnrolling = CGOpts.UnrollLoops; Conf.PTO.LoopInterchange = CGOpts.InterchangeLoops; + Conf.PTO.LoopFusion = CGOpts.FuseLoops; // For historical reasons, loop interleaving is set to mirror setting for loop // unrolling. Conf.PTO.LoopInterleaving = CGOpts.UnrollLoops; diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index a72bdedd7317b..c9377e23086c5 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -6861,6 +6861,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, options::OPT_fno_unroll_loops); Args.AddLastArg(CmdArgs, options::OPT_floop_interchange, options::OPT_fno_loop_interchange); + Args.addOptInFlag(CmdArgs, options::OPT_fexperimental_loop_fusion, + options::OPT_fno_experimental_loop_fusion); Args.AddLastArg(CmdArgs, options::OPT_fstrict_flex_arrays_EQ); diff --git a/clang/lib/Driver/ToolChains/Flang.cpp b/clang/lib/Driver/ToolChains/Flang.cpp index 2118c67dedc54..12e510ab1562d 100644 --- a/clang/lib/Driver/ToolChains/Flang.cpp +++ b/clang/lib/Driver/ToolChains/Flang.cpp @@ -156,6 +156,9 @@ void Flang::addCodegenOptions(const ArgList &Args, !stackArrays->getOption().matches(options::OPT_fno_stack_arrays)) CmdArgs.push_back("-fstack-arrays"); + Args.addOptInFlag(CmdArgs, options::OPT_fexperimental_loop_fusion, + options::OPT_fno_experimental_loop_fusion); + handleInterchangeLoopsArgs(Args, CmdArgs); handleVectorizeLoopsArgs(Args, CmdArgs); handleVectorizeSLPArgs(Args, CmdArgs); diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index 761310813f787..422375240bab6 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -1680,6 +1680,9 @@ void CompilerInvocationBase::GenerateCodeGenArgs(const CodeGenOptions &Opts, else GenerateArg(Consumer, OPT_fno_loop_interchange); + if (Opts.FuseLoops) + GenerateArg(Consumer, OPT_fexperimental_loop_fusion); + if (!Opts.BinutilsVersion.empty()) GenerateArg(Consumer, OPT_fbinutils_version_EQ, Opts.BinutilsVersion); @@ -2001,6 +2004,8 @@ bool CompilerInvocation::ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, (Opts.OptimizationLevel > 1)); Opts.InterchangeLoops = Args.hasFlag(OPT_floop_interchange, OPT_fno_loop_interchange, false); + Opts.FuseLoops = Args.hasFlag(OPT_fexperimental_loop_fusion, + OPT_fno_experimental_loop_fusion, false); Opts.BinutilsVersion = std::string(Args.getLastArgValue(OPT_fbinutils_version_EQ)); diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c index ee7ded265769b..eb3994ddabcd3 100644 --- a/clang/test/Driver/clang_f_opts.c +++ b/clang/test/Driver/clang_f_opts.c @@ -52,6 +52,15 @@ // CHECK-INTERCHANGE-LOOPS: "-floop-interchange" // CHECK-NO-INTERCHANGE-LOOPS: "-fno-loop-interchange" +// RUN: %clang -### -S -fexperimental-loop-fusion %s 2>&1 | FileCheck -check-prefix=CHECK-FUSE-LOOPS %s +// CHECK-FUSE-LOOPS: "-fexperimental-loop-fusion" +// +// RUN: %clang -c -fexperimental-loop-fusion -mllvm -print-pipeline-passes -O3 %s 2>&1 | FileCheck --check-prefixes=LOOP-FUSION-ON %s +// RUN: %clang -c -mllvm -print-pipeline-passes -O3 %s 2>&1 | FileCheck --check-prefixes=LOOP-FUSION-OFF %s + +// LOOP-FUSION-ON: loop-fusion +// LOOP-FUSION-OFF-NOT: loop-fusion + // RUN: %clang -### -S -fprofile-sample-accurate %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-SAMPLE-ACCURATE %s // CHECK-PROFILE-SAMPLE-ACCURATE: "-fprofile-sample-accurate" diff --git a/flang/docs/ReleaseNotes.md b/flang/docs/ReleaseNotes.md index c9623ea08c4e6..6a285f829053b 100644 --- a/flang/docs/ReleaseNotes.md +++ b/flang/docs/ReleaseNotes.md @@ -35,6 +35,8 @@ page](https://llvm.org/releases/). ## New Compiler Flags +* -fexperimental-loop-fusion is now recognized by flang. + ## Windows Support ## Fortran Language Changes in Flang diff --git a/flang/include/flang/Frontend/CodeGenOptions.def b/flang/include/flang/Frontend/CodeGenOptions.def index 22f778c5d3d38..f09159962883f 100644 --- a/flang/include/flang/Frontend/CodeGenOptions.def +++ b/flang/include/flang/Frontend/CodeGenOptions.def @@ -43,6 +43,7 @@ CODEGENOPT(StackArrays, 1, 0) ///< -fstack-arrays (enable the stack-arrays pass) CODEGENOPT(VectorizeLoop, 1, 0) ///< Enable loop vectorization. CODEGENOPT(VectorizeSLP, 1, 0) ///< Enable SLP vectorization. CODEGENOPT(InterchangeLoops, 1, 0) ///< Enable loop interchange. +CODEGENOPT(FuseLoops, 1, 0) ///< Enable loop fusion. CODEGENOPT(LoopVersioning, 1, 0) ///< Enable loop versioning. CODEGENOPT(UnrollLoops, 1, 0) ///< Enable loop unrolling CODEGENOPT(AliasAnalysis, 1, 0) ///< Enable alias analysis pass diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp index c7dbfc46f432c..a00e568bb4a54 100644 --- a/flang/lib/Frontend/CompilerInvocation.cpp +++ b/flang/lib/Frontend/CompilerInvocation.cpp @@ -280,6 +280,9 @@ static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts, if (args.getLastArg(clang::driver::options::OPT_floop_interchange)) opts.InterchangeLoops = 1; + if (args.getLastArg(clang::driver::options::OPT_fexperimental_loop_fusion)) + opts.FuseLoops = 1; + if (args.getLastArg(clang::driver::options::OPT_vectorize_loops)) opts.VectorizeLoop = 1; diff --git a/flang/lib/Frontend/FrontendActions.cpp b/flang/lib/Frontend/FrontendActions.cpp index 3bef6b1c31825..23cc1e63e773d 100644 --- a/flang/lib/Frontend/FrontendActions.cpp +++ b/flang/lib/Frontend/FrontendActions.cpp @@ -958,6 +958,7 @@ void CodeGenAction::runOptimizationPipeline(llvm::raw_pwrite_stream &os) { si.getTimePasses().setOutStream(ci.getTimingStreamLLVM()); pto.LoopUnrolling = opts.UnrollLoops; pto.LoopInterchange = opts.InterchangeLoops; + pto.LoopFusion = opts.FuseLoops; pto.LoopInterleaving = opts.UnrollLoops; pto.LoopVectorization = opts.VectorizeLoop; pto.SLPVectorization = opts.VectorizeSLP; diff --git a/flang/test/Driver/loop-fuse.f90 b/flang/test/Driver/loop-fuse.f90 new file mode 100644 index 0000000000000..ddfd9065e0fd4 --- /dev/null +++ b/flang/test/Driver/loop-fuse.f90 @@ -0,0 +1,17 @@ +! RUN: %flang -### -S -fexperimental-loop-fusion %s 2>&1 | FileCheck -check-prefix=CHECK-LOOP-FUSE %s +! RUN: %flang -### -S -fno-experimental-loop-fusion %s 2>&1 | FileCheck -check-prefix=CHECK-NO-LOOP-FUSE %s +! RUN: %flang -### -S -O0 %s 2>&1 | FileCheck -check-prefix=CHECK-NO-LOOP-FUSE %s +! RUN: %flang -### -S -O1 %s 2>&1 | FileCheck -check-prefix=CHECK-NO-LOOP-FUSE %s +! RUN: %flang -### -S -O2 %s 2>&1 | FileCheck -check-prefix=CHECK-NO-LOOP-FUSE %s +! RUN: %flang -### -S -O3 %s 2>&1 | FileCheck -check-prefix=CHECK-NO-LOOP-FUSE %s +! RUN: %flang -### -S -Os %s 2>&1 | FileCheck -check-prefix=CHECK-NO-LOOP-FUSE %s +! RUN: %flang -### -S -Oz %s 2>&1 | FileCheck -check-prefix=CHECK-NO-LOOP-FUSE %s +! CHECK-LOOP-FUSE: "-fexperimental-loop-fusion" +! CHECK-NO-LOOP-FUSE-NOT: "-fexperimental-loop-fusion" +! RUN: %flang_fc1 -emit-llvm -O2 -fexperimental-loop-fusion -mllvm -print-pipeline-passes -o /dev/null %s 2>&1 | FileCheck -check-prefix=CHECK-LOOP-FUSE-PASS %s +! RUN: %flang_fc1 -emit-llvm -O2 -fno-experimental-loop-fusion -mllvm -print-pipeline-passes -o /dev/null %s 2>&1 | FileCheck -check-prefix=CHECK-NO-LOOP-FUSE-PASS %s +! CHECK-LOOP-FUSE-PASS: loop-fusion +! CHECK-NO-LOOP-FUSE-PASS-NOT: loop-fusion + +program test +end program diff --git a/llvm/include/llvm/Passes/PassBuilder.h b/llvm/include/llvm/Passes/PassBuilder.h index 9cdb7ca7dbc9b..2742ec1b71b7e 100644 --- a/llvm/include/llvm/Passes/PassBuilder.h +++ b/llvm/include/llvm/Passes/PassBuilder.h @@ -65,6 +65,9 @@ class PipelineTuningOptions { /// false. bool LoopInterchange; + /// Tuning option to enable/disable loop fusion. Its default value is false. + bool LoopFusion; + /// Tuning option to forget all SCEV loops in LoopUnroll. Its default value /// is that of the flag: `-forget-scev-loop-unroll`. bool ForgetAllSCEVInLoopUnroll; diff --git a/llvm/lib/Passes/PassBuilderPipelines.cpp b/llvm/lib/Passes/PassBuilderPipelines.cpp index 98821bb1408a7..c3f35f0f5e7fa 100644 --- a/llvm/lib/Passes/PassBuilderPipelines.cpp +++ b/llvm/lib/Passes/PassBuilderPipelines.cpp @@ -104,6 +104,7 @@ #include "llvm/Transforms/Scalar/LoopDeletion.h" #include "llvm/Transforms/Scalar/LoopDistribute.h" #include "llvm/Transforms/Scalar/LoopFlatten.h" +#include "llvm/Transforms/Scalar/LoopFuse.h" #include "llvm/Transforms/Scalar/LoopIdiomRecognize.h" #include "llvm/Transforms/Scalar/LoopInstSimplify.h" #include "llvm/Transforms/Scalar/LoopInterchange.h" @@ -313,6 +314,7 @@ PipelineTuningOptions::PipelineTuningOptions() { SLPVectorization = false; LoopUnrolling = true; LoopInterchange = EnableLoopInterchange; + LoopFusion = false; ForgetAllSCEVInLoopUnroll = ForgetSCEVInLoopUnroll; LicmMssaOptCap = SetLicmMssaOptCap; LicmMssaNoAccForPromotionCap = SetLicmMssaNoAccForPromotionCap; @@ -1551,6 +1553,11 @@ PassBuilder::buildModuleOptimizationPipeline(OptimizationLevel Level, OptimizePM.addPass(createFunctionToLoopPassAdaptor( std::move(LPM), /*UseMemorySSA=*/false, /*UseBlockFrequencyInfo=*/false)); + // FIXME: This may not be the right place in the pipeline. + // We need to have the data to support the right place. + if (PTO.LoopFusion) + OptimizePM.addPass(LoopFusePass()); + // Distribute loops to allow partial vectorization. I.e. isolate dependences // into separate loop that would otherwise inhibit vectorization. This is // currently only performed for loops marked with the metadata @@ -2355,4 +2362,4 @@ AAManager PassBuilder::buildDefaultAAPipeline() { bool PassBuilder::isInstrumentedPGOUse() const { return (PGOOpt && PGOOpt->Action == PGOOptions::IRUse) || !UseCtxProfile.empty(); -} \ No newline at end of file +} diff --git a/llvm/tools/opt/NewPMDriver.cpp b/llvm/tools/opt/NewPMDriver.cpp index b9b8929a0f703..0c991b71a6b26 100644 --- a/llvm/tools/opt/NewPMDriver.cpp +++ b/llvm/tools/opt/NewPMDriver.cpp @@ -60,6 +60,9 @@ cl::opt<bool> VerifyEachDebugInfoPreserve( cl::desc("Start each pass with collecting and end it with checking of " "debug info preservation.")); +static cl::opt<bool> EnableLoopFusion("enable-loopfusion", cl::init(false), + cl::Hidden, + cl::desc("Enable the LoopFuse Pass")); cl::opt<std::string> VerifyDIPreserveExport("verify-di-preserve-export", cl::desc("Export debug info preservation failures into " @@ -446,6 +449,7 @@ bool llvm::runPassPipeline( // option has been enabled. PTO.LoopUnrolling = !DisableLoopUnrolling; PTO.UnifiedLTO = UnifiedLTO; + PTO.LoopFusion = EnableLoopFusion; PassBuilder PB(TM, PTO, P, &PIC); registerEPCallbacks(PB); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
