DAG: Avoid more uses of getLibcallName (#170402)

Author: arsenm

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

@@ -4983,7 +4983,7 @@ static bool isDivRemLibcallAvailable(SDNode *Node, bool isSigned,
   case MVT::i128: LC= isSigned ? RTLIB::SDIVREM_I128:RTLIB::UDIVREM_I128; break;
   }
 
-  return TLI.getLibcallName(LC) != nullptr;
+  return TLI.getLibcallImpl(LC) != RTLIB::Unsupported;
 }
 
 /// Issue divrem if both quotient and remainder are needed.

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -11121,7 +11121,8 @@ void TargetLowering::forceExpandWideMUL(SelectionDAG &DAG, const SDLoc &dl,
   else if (WideVT == MVT::i128)
     LC = RTLIB::MUL_I128;
 
-  if (LC == RTLIB::UNKNOWN_LIBCALL || !getLibcallName(LC)) {
+  RTLIB::LibcallImpl LibcallImpl = getLibcallImpl(LC);
+  if (LibcallImpl == RTLIB::Unsupported) {
     forceExpandMultiply(DAG, dl, Signed, Lo, Hi, LHS, RHS);
     return;
   }