1 files changed, 7 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index a87fbbd989..26e0a5528c 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1104,6 +1104,13 @@ bool InstCombiner::transformConstExprCastCall(CallSite CS) {
     PointerType *APTy = cast<PointerType>(CS.getCalledValue()->getType());
     if (FT->isVarArg()!=cast<FunctionType>(APTy->getElementType())->isVarArg())
       return false;
+
+    // If both the callee and the cast type are varargs, we still have to make
+    // sure the number of fixed parameters are the same or we have the same
+    // ABI issues as if we introduce a varargs call.
+    if (FT->getNumParams() !=
+        cast<FunctionType>(APTy->getElementType())->getNumParams())
+      return false;
   }
       
   if (FT->getNumParams() < NumActualArgs && FT->isVarArg() &&