[flang-commits] [flang] 22544e2 - [flang] Set fast math related function attributes for -Ofast/-ffast-math (#79301)
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flang-commits at lists.llvm.org
Mon Feb 5 11:39:17 PST 2024
Author: Alex Bradbury
Date: 2024-02-05T19:39:12Z
New Revision: 22544e2a54370a3c0b12765981c312f9ec04f1cc
URL: https://github.com/llvm/llvm-project/commit/22544e2a54370a3c0b12765981c312f9ec04f1cc
DIFF: https://github.com/llvm/llvm-project/commit/22544e2a54370a3c0b12765981c312f9ec04f1cc.diff
LOG: [flang] Set fast math related function attributes for -Ofast/-ffast-math (#79301)
The implemented logic matches the logic used for Clang in emitting these
attributes. Although it's hoped that function attributes won't be needed
in the future (vs using fast math flags in individual IR instructions),
there are codegen differences currently with/without these attributes,
as can be seen in issues like #79257 or by hacking Clang to avoid
producing these attributes and observing codegen changes.
Added:
flang/test/Driver/func-attr-fast-math.f90
Modified:
flang/include/flang/Optimizer/Transforms/Passes.h
flang/include/flang/Optimizer/Transforms/Passes.td
flang/include/flang/Tools/CLOptions.inc
flang/include/flang/Tools/CrossToolHelpers.h
flang/lib/Frontend/FrontendActions.cpp
flang/lib/Optimizer/Transforms/FunctionAttr.cpp
Removed:
################################################################################
diff --git a/flang/include/flang/Optimizer/Transforms/Passes.h b/flang/include/flang/Optimizer/Transforms/Passes.h
index aefb277f7966ba..e1d22c8c986da7 100644
--- a/flang/include/flang/Optimizer/Transforms/Passes.h
+++ b/flang/include/flang/Optimizer/Transforms/Passes.h
@@ -92,7 +92,9 @@ struct FunctionAttrTypes {
std::unique_ptr<mlir::Pass> createFunctionAttrPass();
std::unique_ptr<mlir::Pass>
-createFunctionAttrPass(FunctionAttrTypes &functionAttr);
+createFunctionAttrPass(FunctionAttrTypes &functionAttr, bool noInfsFPMath,
+ bool noNaNsFPMath, bool approxFuncFPMath,
+ bool noSignedZerosFPMath, bool unsafeFPMath);
// declarative passes
#define GEN_PASS_REGISTRATION
diff --git a/flang/include/flang/Optimizer/Transforms/Passes.td b/flang/include/flang/Optimizer/Transforms/Passes.td
index 270b83774bcbf3..5fb576fd876254 100644
--- a/flang/include/flang/Optimizer/Transforms/Passes.td
+++ b/flang/include/flang/Optimizer/Transforms/Passes.td
@@ -378,6 +378,21 @@ def FunctionAttr : Pass<"function-attr", "mlir::func::FuncOp"> {
"mlir::LLVM::framePointerKind::FramePointerKind",
/*default=*/"mlir::LLVM::framePointerKind::FramePointerKind{}",
"frame pointer">,
+ Option<"noInfsFPMath", "no-infs-fp-math",
+ "bool", /*default=*/"false",
+ "Set the no-infs-fp-math attribute on functions in the module.">,
+ Option<"noNaNsFPMath", "no-nans-fp-math",
+ "bool", /*default=*/"false",
+ "Set the no-nans-fp-math attribute on functions in the module.">,
+ Option<"approxFuncFPMath", "approx-func-fp-math",
+ "bool", /*default=*/"false",
+ "Set the approx-func-fp-math attribute on functions in the module.">,
+ Option<"noSignedZerosFPMath", "no-signed-zeros-fp-math",
+ "bool", /*default=*/"false",
+ "Set the no-signed-zeros-fp-math attribute on functions in the module.">,
+ Option<"unsafeFPMath", "unsafe-fp-math",
+ "bool", /*default=*/"false",
+ "Set the unsafe-fp-math attribute on functions in the module.">,
];
let constructor = "::fir::createFunctionAttrPass()";
}
diff --git a/flang/include/flang/Tools/CLOptions.inc b/flang/include/flang/Tools/CLOptions.inc
index 8dee3074a5d4f8..68e504d0ccb512 100644
--- a/flang/include/flang/Tools/CLOptions.inc
+++ b/flang/include/flang/Tools/CLOptions.inc
@@ -316,15 +316,22 @@ inline void createDefaultFIRCodeGenPassPipeline(
// Add function attributes
fir::FunctionAttrTypes functionAttrs;
- if (config.FramePointerKind != llvm::FramePointerKind::None) {
+ if (config.FramePointerKind != llvm::FramePointerKind::None ||
+ config.NoInfsFPMath || config.NoNaNsFPMath || config.ApproxFuncFPMath ||
+ config.NoSignedZerosFPMath || config.UnsafeFPMath) {
if (config.FramePointerKind == llvm::FramePointerKind::NonLeaf)
functionAttrs.framePointerKind =
mlir::LLVM::framePointerKind::FramePointerKind::NonLeaf;
- else
+ else if (config.FramePointerKind == llvm::FramePointerKind::All)
functionAttrs.framePointerKind =
mlir::LLVM::framePointerKind::FramePointerKind::All;
+ else
+ functionAttrs.framePointerKind =
+ mlir::LLVM::framePointerKind::FramePointerKind::None;
- pm.addPass(fir::createFunctionAttrPass(functionAttrs));
+ pm.addPass(fir::createFunctionAttrPass(functionAttrs, config.NoInfsFPMath,
+ config.NoNaNsFPMath, config.ApproxFuncFPMath,
+ config.NoSignedZerosFPMath, config.UnsafeFPMath));
}
fir::addFIRToLLVMPass(pm, config);
diff --git a/flang/include/flang/Tools/CrossToolHelpers.h b/flang/include/flang/Tools/CrossToolHelpers.h
index 5c59c99675699d..b7d84af8c483ee 100644
--- a/flang/include/flang/Tools/CrossToolHelpers.h
+++ b/flang/include/flang/Tools/CrossToolHelpers.h
@@ -13,6 +13,7 @@
#ifndef FORTRAN_TOOLS_CROSS_TOOL_HELPERS_H
#define FORTRAN_TOOLS_CROSS_TOOL_HELPERS_H
+#include "flang/Common/MathOptionsBase.h"
#include "flang/Frontend/CodeGenOptions.h"
#include "flang/Frontend/LangOptions.h"
#include <cstdint>
@@ -28,7 +29,8 @@ struct MLIRToLLVMPassPipelineConfig {
OptLevel = level;
}
explicit MLIRToLLVMPassPipelineConfig(llvm::OptimizationLevel level,
- const Fortran::frontend::CodeGenOptions &opts) {
+ const Fortran::frontend::CodeGenOptions &opts,
+ const Fortran::common::MathOptionsBase &mathOpts) {
OptLevel = level;
StackArrays = opts.StackArrays;
Underscoring = opts.Underscoring;
@@ -36,6 +38,15 @@ struct MLIRToLLVMPassPipelineConfig {
DebugInfo = opts.getDebugInfo();
AliasAnalysis = opts.AliasAnalysis;
FramePointerKind = opts.getFramePointer();
+ // The logic for setting these attributes is intended to match the logic
+ // used in Clang.
+ NoInfsFPMath = mathOpts.getNoHonorInfs();
+ NoNaNsFPMath = mathOpts.getNoHonorNaNs();
+ ApproxFuncFPMath = mathOpts.getApproxFunc();
+ NoSignedZerosFPMath = mathOpts.getNoSignedZeros();
+ UnsafeFPMath = mathOpts.getAssociativeMath() &&
+ mathOpts.getReciprocalMath() && NoSignedZerosFPMath &&
+ ApproxFuncFPMath && mathOpts.getFPContractEnabled();
}
llvm::OptimizationLevel OptLevel; ///< optimisation level
@@ -49,6 +60,13 @@ struct MLIRToLLVMPassPipelineConfig {
llvm::FramePointerKind::None; ///< Add frame pointer to functions.
unsigned VScaleMin = 0; ///< SVE vector range minimum.
unsigned VScaleMax = 0; ///< SVE vector range maximum.
+ bool NoInfsFPMath = false; ///< Set no-infs-fp-math attribute for functions.
+ bool NoNaNsFPMath = false; ///< Set no-nans-fp-math attribute for functions.
+ bool ApproxFuncFPMath =
+ false; ///< Set approx-func-fp-math attribute for functions.
+ bool NoSignedZerosFPMath =
+ false; ///< Set no-signed-zeros-fp-math attribute for functions.
+ bool UnsafeFPMath = false; ///< Set unsafe-fp-math attribute for functions.
};
struct OffloadModuleOpts {
diff --git a/flang/lib/Frontend/FrontendActions.cpp b/flang/lib/Frontend/FrontendActions.cpp
index 09e861db3ec6d9..18bc1689c85473 100644
--- a/flang/lib/Frontend/FrontendActions.cpp
+++ b/flang/lib/Frontend/FrontendActions.cpp
@@ -782,6 +782,7 @@ void CodeGenAction::generateLLVMIR() {
CompilerInstance &ci = this->getInstance();
auto opts = ci.getInvocation().getCodeGenOpts();
+ auto mathOpts = ci.getInvocation().getLoweringOpts().getMathOptions();
llvm::OptimizationLevel level = mapToLevel(opts);
fir::support::loadDialects(*mlirCtx);
@@ -794,7 +795,7 @@ void CodeGenAction::generateLLVMIR() {
pm.addPass(std::make_unique<Fortran::lower::VerifierPass>());
pm.enableVerifier(/*verifyPasses=*/true);
- MLIRToLLVMPassPipelineConfig config(level, opts);
+ MLIRToLLVMPassPipelineConfig config(level, opts, mathOpts);
if (auto vsr = getVScaleRange(ci)) {
config.VScaleMin = vsr->first;
diff --git a/flang/lib/Optimizer/Transforms/FunctionAttr.cpp b/flang/lib/Optimizer/Transforms/FunctionAttr.cpp
index 55b908ba5d8613..f54080f21b9675 100644
--- a/flang/lib/Optimizer/Transforms/FunctionAttr.cpp
+++ b/flang/lib/Optimizer/Transforms/FunctionAttr.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "flang/Optimizer/Transforms/Passes.h"
#include "mlir/Dialect/LLVMIR/LLVMAttrs.h"
+#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
namespace fir {
#define GEN_PASS_DECL_FUNCTIONATTR
@@ -27,6 +28,11 @@ class FunctionAttrPass : public fir::impl::FunctionAttrBase<FunctionAttrPass> {
public:
FunctionAttrPass(const fir::FunctionAttrOptions &options) {
framePointerKind = options.framePointerKind;
+ noInfsFPMath = options.noInfsFPMath;
+ noNaNsFPMath = options.noNaNsFPMath;
+ approxFuncFPMath = options.approxFuncFPMath;
+ noSignedZerosFPMath = options.noSignedZerosFPMath;
+ unsafeFPMath = options.unsafeFPMath;
}
FunctionAttrPass() {}
void runOnOperation() override;
@@ -45,14 +51,43 @@ void FunctionAttrPass::runOnOperation() {
func->setAttr("frame_pointer", mlir::LLVM::FramePointerKindAttr::get(
context, framePointerKind));
+ auto llvmFuncOpName =
+ mlir::OperationName(mlir::LLVM::LLVMFuncOp::getOperationName(), context);
+ if (noInfsFPMath)
+ func->setAttr(
+ mlir::LLVM::LLVMFuncOp::getNoInfsFpMathAttrName(llvmFuncOpName),
+ mlir::BoolAttr::get(context, true));
+ if (noNaNsFPMath)
+ func->setAttr(
+ mlir::LLVM::LLVMFuncOp::getNoNansFpMathAttrName(llvmFuncOpName),
+ mlir::BoolAttr::get(context, true));
+ if (approxFuncFPMath)
+ func->setAttr(
+ mlir::LLVM::LLVMFuncOp::getApproxFuncFpMathAttrName(llvmFuncOpName),
+ mlir::BoolAttr::get(context, true));
+ if (noSignedZerosFPMath)
+ func->setAttr(
+ mlir::LLVM::LLVMFuncOp::getNoSignedZerosFpMathAttrName(llvmFuncOpName),
+ mlir::BoolAttr::get(context, true));
+ if (unsafeFPMath)
+ func->setAttr(
+ mlir::LLVM::LLVMFuncOp::getUnsafeFpMathAttrName(llvmFuncOpName),
+ mlir::BoolAttr::get(context, true));
+
LLVM_DEBUG(llvm::dbgs() << "=== End " DEBUG_TYPE " ===\n");
}
-std::unique_ptr<mlir::Pass>
-fir::createFunctionAttrPass(fir::FunctionAttrTypes &functionAttr) {
+std::unique_ptr<mlir::Pass> fir::createFunctionAttrPass(
+ fir::FunctionAttrTypes &functionAttr, bool noInfsFPMath, bool noNaNsFPMath,
+ bool approxFuncFPMath, bool noSignedZerosFPMath, bool unsafeFPMath) {
FunctionAttrOptions opts;
// Frame pointer
opts.framePointerKind = functionAttr.framePointerKind;
+ opts.noInfsFPMath = noInfsFPMath;
+ opts.noNaNsFPMath = noNaNsFPMath;
+ opts.approxFuncFPMath = approxFuncFPMath;
+ opts.noSignedZerosFPMath = noSignedZerosFPMath;
+ opts.unsafeFPMath = unsafeFPMath;
return std::make_unique<FunctionAttrPass>(opts);
}
diff --git a/flang/test/Driver/func-attr-fast-math.f90 b/flang/test/Driver/func-attr-fast-math.f90
new file mode 100644
index 00000000000000..05824a6078a09d
--- /dev/null
+++ b/flang/test/Driver/func-attr-fast-math.f90
@@ -0,0 +1,18 @@
+! RUN: %flang -O1 -emit-llvm -S -o - %s 2>&1| FileCheck %s --check-prefix=CHECK-NOFASTMATH
+! RUN: %flang -Ofast -emit-llvm -S -o - %s 2>&1| FileCheck %s --check-prefix=CHECK-OFAST
+! RUN: %flang -O1 -ffast-math -emit-llvm -S -o - %s 2>&1| FileCheck %s --check-prefix=CHECK-FFAST-MATH
+
+subroutine func
+end subroutine func
+
+! CHECK-NOFASTMATH-LABEL: define void @func_() local_unnamed_addr
+! CHECK-NOFASTMATH-SAME: #[[ATTRS:[0-9]+]]
+! CHECK-NOT fp-math"=
+
+! CHECK-OFAST-LABEL: define void @func_() local_unnamed_addr
+! CHECK-OFAST-SAME: #[[ATTRS:[0-9]+]]
+! CHECK-OFAST: attributes #[[ATTRS]] = { {{.*}}"approx-func-fp-math"="true" {{.*}}"no-infs-fp-math"="true" {{.*}}"no-nans-fp-math"="true" {{.*}}"no-signed-zeros-fp-math"="true" {{.*}}"unsafe-fp-math"="true"{{.*}} }
+
+! CHECK-FFAST-MATH-LABEL: define void @func_() local_unnamed_addr
+! CHECK-FFAST-MATH-SAME: #[[ATTRS:[0-9]+]]
+! CHECK-FFAST-MATH: attributes #[[ATTRS]] = { {{.*}}"approx-func-fp-math"="true" {{.*}}"no-infs-fp-math"="true" {{.*}}"no-nans-fp-math"="true" {{.*}}"no-signed-zeros-fp-math"="true" {{.*}}"unsafe-fp-math"="true"{{.*}} }
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