const FunctionType *FT = Callee->getFunctionType();
const Type *OldRetTy = Caller->getType();
- if (Callee->isExternal() &&
- !OldRetTy->isLosslesslyConvertibleTo(FT->getReturnType()) &&
- !Caller->use_empty())
- return false; // Cannot transform this return value...
+ // Check to see if we are changing the return type...
+ if (OldRetTy != FT->getReturnType()) {
+ if (Callee->isExternal() &&
+ !OldRetTy->isLosslesslyConvertibleTo(FT->getReturnType()) &&
+ !Caller->use_empty())
+ return false; // Cannot transform this return value...
+
+ // If the callsite is an invoke instruction, and the return value is used by
+ // a PHI node in a successor, we cannot change the return type of the call
+ // because there is no place to put the cast instruction (without breaking
+ // the critical edge). Bail out in this case.
+ if (!Caller->use_empty())
+ if (InvokeInst *II = dyn_cast<InvokeInst>(Caller))
+ for (Value::use_iterator UI = II->use_begin(), E = II->use_end();
+ UI != E; ++UI)
+ if (PHINode *PN = dyn_cast<PHINode>(*UI))
+ if (PN->getParent() == II->getNormalDest() ||
+ PN->getParent() == II->getExceptionalDest())
+ return false;
+ }
unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin());
unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs);