[IR] Add AllowContract to FastMathFlags

-ffp-contract=fast does not currently work with LTO because it's passed as a
TargetOption to the backend rather than in the IR. This adds it to
FastMathFlags.

This is toward fixing PR25721

Differential Revision: https://reviews.llvm.org/D31164

llvm-svn: 298939

2 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 4bb0e9fb472..4198d8f7c10 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -971,6 +971,8 @@ static FastMathFlags getDecodedFastMathFlags(unsigned Val) {
     FMF.setNoSignedZeros();
   if (0 != (Val & FastMathFlags::AllowReciprocal))
     FMF.setAllowReciprocal();
+  if (0 != (Val & FastMathFlags::AllowContract))
+    FMF.setAllowContract(true);
   return FMF;
 }
 
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index b1200587e62..1bdb439086a 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1336,6 +1336,8 @@ static uint64_t getOptimizationFlags(const Value *V) {
       Flags |= FastMathFlags::NoSignedZeros;
     if (FPMO->hasAllowReciprocal())
       Flags |= FastMathFlags::AllowReciprocal;
+    if (FPMO->hasAllowContract())
+      Flags |= FastMathFlags::AllowContract;
   }
 
   return Flags;