Fix bitcast-to-base pattern for library function argument (#3845)

Author: tex3d

lib/Transforms/Scalar/ScalarReplAggregatesHLSL.cpp

@@ -5442,6 +5442,7 @@ static void LegalizeDxilInputOutputs(Function *F,
   // Map from output to the temp created for it.
   MapVector<Argument *, Value*> outputTempMap; // Need deterministic order of iteration
   for (Argument &arg : F->args()) {
+    HLModule::MergeGepUse(&arg);
     Type *Ty = arg.getType();
 
     DxilParameterAnnotation &paramAnnotation = EntryAnnotation->GetParameterAnnotation(arg.getArgNo());