1 files changed, 8 insertions, 7 deletions
diff --git a/lib/CodeGen/BackendUtil.cpp b/lib/CodeGen/BackendUtil.cpp
index 855d6795b9d6c..20059d922f90b 100644
--- a/lib/CodeGen/BackendUtil.cpp
+++ b/lib/CodeGen/BackendUtil.cpp
@@ -83,9 +83,6 @@ class EmitAssemblyHelper {
     return TargetIRAnalysis();
   }
 
-  /// Set LLVM command line options passed through -backend-option.
-  void setCommandLineOpts();
-
   void CreatePasses(legacy::PassManager &MPM, legacy::FunctionPassManager &FPM);
 
   /// Generates the TargetMachine.
@@ -372,7 +369,9 @@ static void initTargetOptions(llvm::TargetOptions &Options,
   // 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;
@@ -604,7 +603,7 @@ void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
   PMBuilder.populateModulePassManager(MPM);
 }
 
-void EmitAssemblyHelper::setCommandLineOpts() {
+static void setCommandLineOpts(const CodeGenOptions &CodeGenOpts) {
   SmallVector<const char *, 16> BackendArgs;
   BackendArgs.push_back("clang"); // Fake program name.
   if (!CodeGenOpts.DebugPass.empty()) {
@@ -677,7 +676,7 @@ void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
                                       std::unique_ptr<raw_pwrite_stream> OS) {
   TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : nullptr);
 
-  setCommandLineOpts();
+  setCommandLineOpts(CodeGenOpts);
 
   bool UsesCodeGen = (Action != Backend_EmitNothing &&
                       Action != Backend_EmitBC &&
@@ -806,7 +805,7 @@ static PassBuilder::OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
 void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
     BackendAction Action, std::unique_ptr<raw_pwrite_stream> OS) {
   TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : nullptr);
-  setCommandLineOpts();
+  setCommandLineOpts(CodeGenOpts);
 
   // The new pass manager always makes a target machine available to passes
   // during construction.
@@ -944,6 +943,8 @@ static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
       ModuleToDefinedGVSummaries;
   CombinedIndex->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
 
+  setCommandLineOpts(CGOpts);
+
   // We can simply import the values mentioned in the combined index, since
   // we should only invoke this using the individual indexes written out
   // via a WriteIndexesThinBackend.