Don't pass FPOpFusion::Strict to the backend
This restores the behavior prior to D31167 where the code-gen default was
FPC_On which mapped to FPOpFusion::Standard. After merging the FE
state (on/off) and the code-gen state (on/fast/off), the default became off to
match the front-end.
In other words, the front-end controls when to fuse along the language
standards and the backend shouldn't override this by splitting fused
intrinsics as FPOpFusion::Strict would imply.
Differential Revision: https://reviews.llvm.org/D32301
llvm-svn: 300858
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 3f95740..20059d9 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -369,7 +369,9 @@
// Set FP fusion mode.
switch (LangOpts.getDefaultFPContractMode()) {
case LangOptions::FPC_Off:
- Options.AllowFPOpFusion = llvm::FPOpFusion::Strict;
+ // Preserve any contraction performed by the front-end. (Strict performs
+ // splitting of the muladd instrinsic in the backend.)
+ Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
break;
case LangOptions::FPC_On:
Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;