2 files changed, 14 insertions, 1 deletions
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 9cbba066547..f4b483b5158 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -22,8 +22,9 @@
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/StmtCXX.h"
 #include "clang/Frontend/CodeGenOptions.h"
-#include "llvm/Target/TargetData.h"
 #include "llvm/Intrinsics.h"
+#include "llvm/Support/MDBuilder.h"
+#include "llvm/Target/TargetData.h"
 using namespace clang;
 using namespace CodeGen;
 
@@ -41,6 +42,10 @@ CodeGenFunction::CodeGenFunction(CodeGenModule &cgm)
     TerminateHandler(0), TrapBB(0) {
 
   CatchUndefined = getContext().getLangOpts().CatchUndefined;
+  if (getContext().getLangOpts().FastMath) {
+    llvm::MDBuilder MDHelper(Builder.getContext());
+    Builder.SetDefaultFPMathTag(MDHelper.createFastFPMath());
+  }
   CGM.getCXXABI().getMangleContext().startNewFunction();
 }
 
diff --git a/clang/test/CodeGen/2012-04-16-FastMath.c b/clang/test/CodeGen/2012-04-16-FastMath.c
new file mode 100644
index 00000000000..d7c3d9a2d63
--- /dev/null
+++ b/clang/test/CodeGen/2012-04-16-FastMath.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 %s -ffast-math -emit-llvm -o - | FileCheck %s
+
+double add(double x, double y) {
+// CHECK: @add
+  return x + y;
+// CHECK: fadd double %{{.}}, %{{.}}, !fpmath !0
+}
+// CHECK: !0 = metadata !{metadata !"fast"}