1 files changed, 6 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/X86FastISel.cpp b/llvm/lib/Target/X86/X86FastISel.cpp
index 2a44803f5a1..811887bdc61 100644
--- a/llvm/lib/Target/X86/X86FastISel.cpp
+++ b/llvm/lib/Target/X86/X86FastISel.cpp
@@ -30,6 +30,7 @@
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/Support/CallSite.h"
 #include "llvm/Support/GetElementPtrTypeIterator.h"
+#include "llvm/Target/TargetOptions.h"
 using namespace llvm;
 
 namespace {
@@ -1115,6 +1116,11 @@ bool X86FastISel::X86SelectCall(Instruction *I) {
       CC != CallingConv::X86_FastCall)
     return false;
 
+  // On X86, -tailcallopt changes the fastcc ABI. FastISel doesn't
+  // handle this for now.
+  if (CC == CallingConv::Fast && PerformTailCallOpt)
+    return false;
+
   // Let SDISel handle vararg functions.
   const PointerType *PT = cast<PointerType>(CS.getCalledValue()->getType());
   const FunctionType *FTy = cast<FunctionType>(PT->getElementType());