Update FP option rendering to leave denormal-fp-math alone

Author: Andy Kaylor

clang/lib/Driver/ToolChains/Clang.cpp

@@ -2743,13 +2743,11 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
   StringRef FPExceptionBehavior = "";
   // -ffp-eval-method options: double, extended, source
   StringRef FPEvalMethod = "";
-  const llvm::DenormalMode DefaultDenormalFPMath =
+  llvm::DenormalMode DenormalFPMath =
       TC.getDefaultDenormalModeForType(Args, JA);
-  const llvm::DenormalMode DefaultDenormalFP32Math =
+  llvm::DenormalMode DenormalFP32Math =
       TC.getDefaultDenormalModeForType(Args, JA, &llvm::APFloat::IEEEsingle());
 
-  llvm::DenormalMode DenormalFPMath = DefaultDenormalFPMath;
-  llvm::DenormalMode DenormalFP32Math = DefaultDenormalFP32Math;
   // CUDA and HIP don't rely on the frontend to pass an ffp-contract option.
   // If one wasn't given by the user, don't pass it here.
   StringRef FPContract;
@@ -2899,11 +2897,6 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
       SignedZeros = true;
       // -fno_fast_math restores default denormal and fpcontract handling
       FPContract = "on";
-      DenormalFPMath = llvm::DenormalMode::getIEEE();
-
-      // FIXME: The target may have picked a non-IEEE default mode here based on
-      // -cl-denorms-are-zero. Should the target consider -fp-model interaction?
-      DenormalFP32Math = llvm::DenormalMode::getIEEE();
 
       StringRef Val = A->getValue();
       if (OFastEnabled && !Val.equals("fast")) {
@@ -2924,10 +2917,6 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
       if (Val.equals("fast")) {
         FPModel = Val;
         applyFastMath();
-        // The target-specific getDefaultDenormalModeForType handler should
-        // account for -ffp-model=fast and choose its behavior
-        DenormalFPMath = DefaultDenormalFPMath;
-        DenormalFP32Math = DefaultDenormalFP32Math;
       } else if (Val.equals("precise")) {
         optID = options::OPT_ffp_contract;
         FPModel = Val;
@@ -3126,9 +3115,6 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
       TrappingMath = true;
       FPExceptionBehavior = "strict";
 
-      // The target may have opted to flush by default, so force IEEE.
-      DenormalFPMath = llvm::DenormalMode::getIEEE();
-      DenormalFP32Math = llvm::DenormalMode::getIEEE();
       if (!JA.isDeviceOffloading(Action::OFK_Cuda) &&
           !JA.isOffloading(Action::OFK_HIP)) {
         if (LastSeenFfpContractOption != "") {
@@ -3158,9 +3144,7 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
       ReciprocalMath = false;
       ApproxFunc = false;
       SignedZeros = true;
-      // -fno_fast_math restores default denormal and fpcontract handling
-      DenormalFPMath = DefaultDenormalFPMath;
-      DenormalFP32Math = llvm::DenormalMode::getIEEE();
+      // -fno_fast_math restores default fpcontract handling
       if (!JA.isDeviceOffloading(Action::OFK_Cuda) &&
           !JA.isOffloading(Action::OFK_HIP)) {
         if (LastSeenFfpContractOption != "") {
@@ -3175,8 +3159,6 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
       // subsequent options conflict then emit warning diagnostic.
       if (HonorINFs && HonorNaNs && !AssociativeMath && !ReciprocalMath &&
           SignedZeros && TrappingMath && RoundingFPMath && !ApproxFunc &&
-          DenormalFPMath == llvm::DenormalMode::getIEEE() &&
-          DenormalFP32Math == llvm::DenormalMode::getIEEE() &&
           FPContract.equals("off"))
         // OK: Current Arg doesn't conflict with -ffp-model=strict
         ;