[Mlir-commits] [mlir] [flang] [flang] Set fast math related function attributes for -Ofast/-ffast-math (PR #79301)

Alex Bradbury llvmlistbot at llvm.org
Mon Jan 29 03:49:28 PST 2024


https://github.com/asb updated https://github.com/llvm/llvm-project/pull/79301

>From 1e2881bb92f34d80c1c2d132eacf3a8b416d8b84 Mon Sep 17 00:00:00 2001
From: Alex Bradbury <asb at igalia.com>
Date: Sun, 28 Jan 2024 14:40:49 +0000
Subject: [PATCH 1/3] [MLIR][LLVM] Add fast-math related function attribute
 support

Adds unsafe-fp-math, no-infs-fp-math, no-nans-fp-math,
approx-func-fp-math, and no-signed-zeros-fp-math function attributes.
---
 mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td   |  7 ++-
 mlir/lib/Target/LLVMIR/ModuleImport.cpp       | 25 +++++++++++
 mlir/lib/Target/LLVMIR/ModuleTranslation.cpp  | 18 ++++++++
 mlir/test/Dialect/LLVMIR/func.mlir            | 30 +++++++++++++
 .../LLVMIR/Import/function-attributes.ll      | 30 +++++++++++++
 .../LLVMIR/fp-math-function-attributes.mlir   | 44 +++++++++++++++++++
 6 files changed, 153 insertions(+), 1 deletion(-)
 create mode 100644 mlir/test/Target/LLVMIR/fp-math-function-attributes.mlir

diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
index 01d476f530b1c57..ad67fba5a81cf8b 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
@@ -1428,7 +1428,12 @@ def LLVM_LLVMFuncOp : LLVM_Op<"func", [
     OptionalAttr<LLVM_VScaleRangeAttr>:$vscale_range,
     OptionalAttr<FramePointerKindAttr>:$frame_pointer,
     OptionalAttr<StrAttr>:$target_cpu,
-    OptionalAttr<LLVM_TargetFeaturesAttr>:$target_features
+    OptionalAttr<LLVM_TargetFeaturesAttr>:$target_features,
+    OptionalAttr<BoolAttr>:$unsafe_fp_math,
+    OptionalAttr<BoolAttr>:$no_infs_fp_math,
+    OptionalAttr<BoolAttr>:$no_nans_fp_math,
+    OptionalAttr<BoolAttr>:$approx_func_fp_math,
+    OptionalAttr<BoolAttr>:$no_signed_zeros_fp_math
   );
 
   let regions = (region AnyRegion:$body);
diff --git a/mlir/lib/Target/LLVMIR/ModuleImport.cpp b/mlir/lib/Target/LLVMIR/ModuleImport.cpp
index 928d8077175ccf5..5ca4a9fd68d650d 100644
--- a/mlir/lib/Target/LLVMIR/ModuleImport.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleImport.cpp
@@ -1646,6 +1646,11 @@ static constexpr std::array ExplicitAttributes{
     StringLiteral("vscale_range"),
     StringLiteral("frame-pointer"),
     StringLiteral("target-features"),
+    StringLiteral("unsafe-fp-math"),
+    StringLiteral("no-infs-fp-math"),
+    StringLiteral("no-nans-fp-math"),
+    StringLiteral("approx-func-fp-math"),
+    StringLiteral("no-signed-zeros-fp-math"),
 };
 
 static void processPassthroughAttrs(llvm::Function *func, LLVMFuncOp funcOp) {
@@ -1752,6 +1757,26 @@ void ModuleImport::processFunctionAttributes(llvm::Function *func,
       attr.isStringAttribute())
     funcOp.setTargetFeaturesAttr(
         LLVM::TargetFeaturesAttr::get(context, attr.getValueAsString()));
+
+  if (llvm::Attribute attr = func->getFnAttribute("unsafe-fp-math");
+      attr.isStringAttribute())
+    funcOp.setUnsafeFpMath(attr.getValueAsBool());
+
+  if (llvm::Attribute attr = func->getFnAttribute("no-infs-fp-math");
+      attr.isStringAttribute())
+    funcOp.setNoInfsFpMath(attr.getValueAsBool());
+
+  if (llvm::Attribute attr = func->getFnAttribute("no-nans-fp-math");
+      attr.isStringAttribute())
+    funcOp.setNoNansFpMath(attr.getValueAsBool());
+
+  if (llvm::Attribute attr = func->getFnAttribute("approx-func-fp-math");
+      attr.isStringAttribute())
+    funcOp.setApproxFuncFpMath(attr.getValueAsBool());
+
+  if (llvm::Attribute attr = func->getFnAttribute("no-signed-zeros-fp-math");
+      attr.isStringAttribute())
+    funcOp.setNoSignedZerosFpMath(attr.getValueAsBool());
 }
 
 DictionaryAttr
diff --git a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
index 69a1cbe5969e859..6364cacbd19245f 100644
--- a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
@@ -37,6 +37,7 @@
 
 #include "llvm/ADT/PostOrderIterator.h"
 #include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/TypeSwitch.h"
 #include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
 #include "llvm/IR/BasicBlock.h"
@@ -1214,6 +1215,23 @@ LogicalResult ModuleTranslation::convertOneFunction(LLVMFuncOp func) {
         getLLVMContext(), attr->getMinRange().getInt(),
         attr->getMaxRange().getInt()));
 
+  if (auto unsafeFpMath = func.getUnsafeFpMath())
+    llvmFunc->addFnAttr("unsafe-fp-math", llvm::toStringRef(*unsafeFpMath));
+
+  if (auto noInfsFpMath = func.getNoInfsFpMath())
+    llvmFunc->addFnAttr("no-infs-fp-math", llvm::toStringRef(*noInfsFpMath));
+
+  if (auto noNansFpMath = func.getNoNansFpMath())
+    llvmFunc->addFnAttr("no-nans-fp-math", llvm::toStringRef(*noNansFpMath));
+
+  if (auto approxFuncFpMath = func.getApproxFuncFpMath())
+    llvmFunc->addFnAttr("approx-func-fp-math",
+                        llvm::toStringRef(*approxFuncFpMath));
+
+  if (auto noSignedZerosFpMath = func.getNoSignedZerosFpMath())
+    llvmFunc->addFnAttr("no-signed-zeros-fp-math",
+                        llvm::toStringRef(*noSignedZerosFpMath));
+
   // Add function attribute frame-pointer, if found.
   if (FramePointerKindAttr attr = func.getFramePointerAttr())
     llvmFunc->addFnAttr("frame-pointer",
diff --git a/mlir/test/Dialect/LLVMIR/func.mlir b/mlir/test/Dialect/LLVMIR/func.mlir
index 9dc1bc57034e02f..006f2f64a27277c 100644
--- a/mlir/test/Dialect/LLVMIR/func.mlir
+++ b/mlir/test/Dialect/LLVMIR/func.mlir
@@ -257,6 +257,36 @@ module {
   llvm.func @frame_pointer_roundtrip() attributes {frame_pointer = #llvm.framePointerKind<"non-leaf">} {
     llvm.return
   }
+
+  llvm.func @unsafe_fp_math_roundtrip() attributes {unsafe_fp_math = true} {
+    // CHECK: @unsafe_fp_math_roundtrip
+    // CHECK-SAME: attributes {unsafe_fp_math = true}
+    llvm.return
+  }
+
+  llvm.func @no_infs_fp_math_roundtrip() attributes {no_infs_fp_math = true} {
+    // CHECK: @no_infs_fp_math_roundtrip
+    // CHECK-SAME: attributes {no_infs_fp_math = true}
+    llvm.return
+  }
+
+  llvm.func @no_nans_fp_math_roundtrip() attributes {no_nans_fp_math = true} {
+    // CHECK: @no_nans_fp_math_roundtrip
+    // CHECK-SAME: attributes {no_nans_fp_math = true}
+    llvm.return
+  }
+
+  llvm.func @approx_func_fp_math_roundtrip() attributes {approx_func_fp_math = true} {
+    // CHECK: @approx_func_fp_math_roundtrip
+    // CHECK-SAME: attributes {approx_func_fp_math = true}
+    llvm.return
+  }
+
+  llvm.func @no_signed_zeros_fp_math_roundtrip() attributes {no_signed_zeros_fp_math = true} {
+    // CHECK: @no_signed_zeros_fp_math_roundtrip
+    // CHECK-SAME: attributes {no_signed_zeros_fp_math = true}
+    llvm.return
+  }
 }
 
 // -----
diff --git a/mlir/test/Target/LLVMIR/Import/function-attributes.ll b/mlir/test/Target/LLVMIR/Import/function-attributes.ll
index af2ef9db96ae333..70387789aa97e4a 100644
--- a/mlir/test/Target/LLVMIR/Import/function-attributes.ll
+++ b/mlir/test/Target/LLVMIR/Import/function-attributes.ll
@@ -272,3 +272,33 @@ define void @align_func() align 2 {
 ; CHECK-LABEL: @align_decl
 ; CHECK-SAME: attributes {alignment = 64 : i64}
 declare void @align_decl() align 64
+
+; // -----
+
+; CHECK-LABEL: @func_attr_unsafe_fp_math
+; CHECK-SAME: attributes {unsafe_fp_math = true}
+declare void @func_attr_unsafe_fp_math() "unsafe-fp-math"="true"
+
+; // -----
+
+; CHECK-LABEL: @func_attr_no_infs_fp_math
+; CHECK-SAME: attributes {no_infs_fp_math = true}
+declare void @func_attr_no_infs_fp_math() "no-infs-fp-math"="true"
+
+; // -----
+
+; CHECK-LABEL: @func_attr_no_nans_fp_math
+; CHECK-SAME: attributes {no_nans_fp_math = true}
+declare void @func_attr_no_nans_fp_math() "no-nans-fp-math"="true"
+
+; // -----
+
+; CHECK-LABEL: @func_attr_approx_func_fp_math
+; CHECK-SAME: attributes {approx_func_fp_math = true}
+declare void @func_attr_approx_func_fp_math() "approx-func-fp-math"="true"
+
+; // -----
+
+; CHECK-LABEL: @func_attr_no_signed_zeros_fp_math
+; CHECK-SAME: attributes {no_signed_zeros_fp_math = true}
+declare void @func_attr_no_signed_zeros_fp_math() "no-signed-zeros-fp-math"="true"
diff --git a/mlir/test/Target/LLVMIR/fp-math-function-attributes.mlir b/mlir/test/Target/LLVMIR/fp-math-function-attributes.mlir
new file mode 100644
index 000000000000000..ccae06cc3dd76d6
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/fp-math-function-attributes.mlir
@@ -0,0 +1,44 @@
+// RUN: mlir-translate -mlir-to-llvmir -split-input-file %s | FileCheck %s
+
+// CHECK-LABEL: define void @unsafe_fp_math_func()
+// CHECK-SAME: #[[ATTRS:[0-9]+]]
+llvm.func @unsafe_fp_math_func() attributes {unsafe_fp_math = true}  {
+  llvm.return
+}
+// CHECK: attributes #[[ATTRS]] = { "unsafe-fp-math"="true" }
+
+// -----
+
+// CHECK-LABEL: define void @no_infs_fp_math_func()
+// CHECK-SAME: #[[ATTRS:[0-9]+]]
+llvm.func @no_infs_fp_math_func() attributes {no_infs_fp_math = true}  {
+  llvm.return
+}
+// CHECK: attributes #[[ATTRS]] = { "no-infs-fp-math"="true" }
+
+// -----
+
+// CHECK-LABEL: define void @no_nans_fp_math_func()
+// CHECK-SAME: #[[ATTRS:[0-9]+]]
+llvm.func @no_nans_fp_math_func() attributes {no_nans_fp_math = true}  {
+  llvm.return
+}
+// CHECK: attributes #[[ATTRS]] = { "no-nans-fp-math"="true" }
+
+// -----
+
+// CHECK-LABEL: define void @approx_func_fp_math_func()
+// CHECK-SAME: #[[ATTRS:[0-9]+]]
+llvm.func @approx_func_fp_math_func() attributes {approx_func_fp_math = true}  {
+  llvm.return
+}
+// CHECK: attributes #[[ATTRS]] = { "approx-func-fp-math"="true" }
+
+// -----
+
+// CHECK-LABEL: define void @no_signed_zeros_fp_math_func()
+// CHECK-SAME: #[[ATTRS:[0-9]+]]
+llvm.func @no_signed_zeros_fp_math_func() attributes {no_signed_zeros_fp_math = true}  {
+  llvm.return
+}
+// CHECK: attributes #[[ATTRS]] = { "no-signed-zeros-fp-math"="true" }

>From e245fcd5e33abb73092c0eeab69b0d1ad688c88c Mon Sep 17 00:00:00 2001
From: Alex Bradbury <asb at igalia.com>
Date: Mon, 29 Jan 2024 11:25:56 +0000
Subject: [PATCH 2/3] [flang] Set fast math related function attributes for
 -Ofast/-ffast-math

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.
---
 .../flang/Optimizer/Transforms/Passes.h       |  4 ++-
 .../flang/Optimizer/Transforms/Passes.td      | 15 +++++++++++
 flang/include/flang/Tools/CLOptions.inc       | 15 ++++++++---
 flang/include/flang/Tools/CrossToolHelpers.h  | 20 +++++++++++++-
 flang/lib/Frontend/FrontendActions.cpp        |  3 ++-
 .../lib/Optimizer/Transforms/FunctionAttr.cpp | 27 +++++++++++++++++--
 flang/test/Driver/func-attr-fast-math.f90     | 20 ++++++++++++++
 7 files changed, 96 insertions(+), 8 deletions(-)
 create mode 100644 flang/test/Driver/func-attr-fast-math.f90

diff --git a/flang/include/flang/Optimizer/Transforms/Passes.h b/flang/include/flang/Optimizer/Transforms/Passes.h
index 6970da8698ae84d..d33623c6904891e 100644
--- a/flang/include/flang/Optimizer/Transforms/Passes.h
+++ b/flang/include/flang/Optimizer/Transforms/Passes.h
@@ -91,7 +91,9 @@ 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 e3c45d41f04cc71..397985383b226c7 100644
--- a/flang/include/flang/Optimizer/Transforms/Passes.td
+++ b/flang/include/flang/Optimizer/Transforms/Passes.td
@@ -366,6 +366,21 @@ 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 96d3869cd093912..7a327ad226bf7e6 100644
--- a/flang/include/flang/Tools/CLOptions.inc
+++ b/flang/include/flang/Tools/CLOptions.inc
@@ -315,15 +315,24 @@ 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 b61224ff4f1b3cd..0f39bdb86102f2c 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 65c4df7388f97b2..17d5670b4134d86 100644
--- a/flang/lib/Frontend/FrontendActions.cpp
+++ b/flang/lib/Frontend/FrontendActions.cpp
@@ -787,6 +787,7 @@ 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);
@@ -799,7 +800,7 @@ 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 55b908ba5d86139..55ffc4ed43933a8 100644
--- a/flang/lib/Optimizer/Transforms/FunctionAttr.cpp
+++ b/flang/lib/Optimizer/Transforms/FunctionAttr.cpp
@@ -27,6 +27,11 @@ 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 +50,32 @@ void FunctionAttrPass::runOnOperation() {
     func->setAttr("frame_pointer", mlir::LLVM::FramePointerKindAttr::get(
                                        context, framePointerKind));
 
+  if (noInfsFPMath)
+    func->setAttr("no_infs_fp_math", mlir::BoolAttr::get(context, true));
+  if (noNaNsFPMath)
+    func->setAttr("no_nans_fp_math", mlir::BoolAttr::get(context, true));
+  if (approxFuncFPMath)
+    func->setAttr("approx_func_fp_math", mlir::BoolAttr::get(context, true));
+  if (noSignedZerosFPMath)
+    func->setAttr("no_signed_zeros_fp_math",
+                  mlir::BoolAttr::get(context, true));
+  if (unsafeFPMath)
+    func->setAttr("unsafe_fp_math", 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 000000000000000..2f078dd1b218365
--- /dev/null
+++ b/flang/test/Driver/func-attr-fast-math.f90
@@ -0,0 +1,20 @@
+! Test that -mframe-pointer can accept only specific values and when given an invalid value, check it raises an error.
+
+! 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-NOFASTMATH: attributes #[[ATTRS]] = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) }
+!
+! CHECK-OFAST-LABEL: define void @func_() local_unnamed_addr
+! CHECK-OFAST-SAME: #[[ATTRS:[0-9]+]]
+! CHECK-OFAST: attributes #[[ATTRS]] = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) "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]] = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) "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" }

>From a39abb413a5351e30d76eabe02d578e90ea8f5c8 Mon Sep 17 00:00:00 2001
From: Alex Bradbury <asb at igalia.com>
Date: Mon, 29 Jan 2024 11:49:11 +0000
Subject: [PATCH 3/3] clang-format .inc changes

---
 flang/include/flang/Tools/CLOptions.inc | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/flang/include/flang/Tools/CLOptions.inc b/flang/include/flang/Tools/CLOptions.inc
index 7a327ad226bf7e6..166ba5f58774d76 100644
--- a/flang/include/flang/Tools/CLOptions.inc
+++ b/flang/include/flang/Tools/CLOptions.inc
@@ -315,7 +315,7 @@ 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)
@@ -328,11 +328,9 @@ inline void createDefaultFIRCodeGenPassPipeline(
       functionAttrs.framePointerKind =
           mlir::LLVM::framePointerKind::FramePointerKind::None;
 
-    pm.addPass(
-      fir::createFunctionAttrPass(functionAttrs, config.NoInfsFPMath,
-                                  config.NoNaNsFPMath, config.ApproxFuncFPMath,
-                                  config.NoSignedZerosFPMath,
-                                  config.UnsafeFPMath));
+    pm.addPass(fir::createFunctionAttrPass(functionAttrs, config.NoInfsFPMath,
+        config.NoNaNsFPMath, config.ApproxFuncFPMath,
+        config.NoSignedZerosFPMath, config.UnsafeFPMath));
   }
 
   fir::addFIRToLLVMPass(pm, config);



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