Reland D81869 "Modify FPFeatures to use delta not absolute settings"

This reverts commit defd43a5b393bb63a902042adf578081b03b171d.
with correction to solve msan report

To solve https://bugs.llvm.org/show_bug.cgi?id=46166 where the
floating point settings in PCH files aren't compatible, rewrite
FPFeatures to use a delta in the settings rather than absolute settings.
With this patch, these floating point options can be benign.

Reviewers: rjmccall

Differential Revision: https://reviews.llvm.org/D81869

1 files changed, 17 insertions, 15 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 23208b2d..cfd32d1 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -117,12 +117,12 @@ void CodeGenFunction::SetFPModel() {
 
 void CodeGenFunction::SetFastMathFlags(FPOptions FPFeatures) {
   llvm::FastMathFlags FMF;
-  FMF.setAllowReassoc(FPFeatures.allowAssociativeMath());
-  FMF.setNoNaNs(FPFeatures.noHonorNaNs());
-  FMF.setNoInfs(FPFeatures.noHonorInfs());
-  FMF.setNoSignedZeros(FPFeatures.noSignedZeros());
-  FMF.setAllowReciprocal(FPFeatures.allowReciprocalMath());
-  FMF.setApproxFunc(FPFeatures.allowApproximateFunctions());
+  FMF.setAllowReassoc(FPFeatures.getAllowFPReassociate());
+  FMF.setNoNaNs(FPFeatures.getNoHonorNaNs());
+  FMF.setNoInfs(FPFeatures.getNoHonorInfs());
+  FMF.setNoSignedZeros(FPFeatures.getNoSignedZero());
+  FMF.setAllowReciprocal(FPFeatures.getAllowReciprocal());
+  FMF.setApproxFunc(FPFeatures.getAllowApproxFunc());
   FMF.setAllowContract(FPFeatures.allowFPContractAcrossStatement());
   Builder.setFastMathFlags(FMF);
 }
@@ -137,10 +137,12 @@ CodeGenFunction::CGFPOptionsRAII::CGFPOptionsRAII(CodeGenFunction &CGF,
 
   FMFGuard.emplace(CGF.Builder);
 
-  auto NewRoundingBehavior = FPFeatures.getRoundingMode();
+  llvm::RoundingMode NewRoundingBehavior =
+      static_cast<llvm::RoundingMode>(FPFeatures.getRoundingMode());
   CGF.Builder.setDefaultConstrainedRounding(NewRoundingBehavior);
   auto NewExceptionBehavior =
-      ToConstrainedExceptMD(FPFeatures.getExceptionMode());
+      ToConstrainedExceptMD(static_cast<LangOptions::FPExceptionModeKind>(
+          FPFeatures.getFPExceptionMode()));
   CGF.Builder.setDefaultConstrainedExcept(NewExceptionBehavior);
 
   CGF.SetFastMathFlags(FPFeatures);
@@ -159,13 +161,13 @@ CodeGenFunction::CGFPOptionsRAII::CGFPOptionsRAII(CodeGenFunction &CGF,
     if (OldValue != NewValue)
       CGF.CurFn->addFnAttr(Name, llvm::toStringRef(NewValue));
   };
-  mergeFnAttrValue("no-infs-fp-math", FPFeatures.noHonorInfs());
-  mergeFnAttrValue("no-nans-fp-math", FPFeatures.noHonorNaNs());
-  mergeFnAttrValue("no-signed-zeros-fp-math", FPFeatures.noSignedZeros());
-  mergeFnAttrValue(
-      "unsafe-fp-math",
-      FPFeatures.allowAssociativeMath() && FPFeatures.allowReciprocalMath() &&
-          FPFeatures.allowApproximateFunctions() && FPFeatures.noSignedZeros());
+  mergeFnAttrValue("no-infs-fp-math", FPFeatures.getNoHonorInfs());
+  mergeFnAttrValue("no-nans-fp-math", FPFeatures.getNoHonorNaNs());
+  mergeFnAttrValue("no-signed-zeros-fp-math", FPFeatures.getNoSignedZero());
+  mergeFnAttrValue("unsafe-fp-math", FPFeatures.getAllowFPReassociate() &&
+                                         FPFeatures.getAllowReciprocal() &&
+                                         FPFeatures.getAllowApproxFunc() &&
+                                         FPFeatures.getNoSignedZero());
 }
 
 CodeGenFunction::CGFPOptionsRAII::~CGFPOptionsRAII() {