// visitCallSite - Improvements for call and invoke instructions.
//
Instruction *InstCombiner::visitCallSite(CallSite CS) {
+ bool Changed = false;
+
+ // If the callee is a constexpr cast of a function, attempt to move the cast
+ // to the arguments of the call/invoke.
if (transformConstExprCastCall(CS)) return 0;
+ Value *Callee = CS.getCalledValue();
+ const PointerType *PTy = cast<PointerType>(Callee->getType());
+ const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
+ if (FTy->isVarArg()) {
+ // See if we can optimize any arguments passed through the varargs area of
+ // the call.
+ for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(),
+ E = CS.arg_end(); I != E; ++I)
+ if (CastInst *CI = dyn_cast<CastInst>(*I)) {
+ // If this cast does not effect the value passed through the varargs
+ // area, we can eliminate the use of the cast.
+ Value *Op = CI->getOperand(0);
+ if (CI->getType()->isLosslesslyConvertibleTo(Op->getType())) {
+ *I = Op;
+ Changed = true;
+ }
+ }
+ }
- return 0;
+ return Changed ? CS.getInstruction() : 0;
}
// transformConstExprCastCall - If the callee is a constexpr cast of a function,