DAG: Remove unnecessary getPointerTy call (#154055)

getValueType already did this

Author: arsenm

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -1837,11 +1837,8 @@ SDValue SelectionDAGBuilder::getValueImpl(const Value *V) {
                          getValue(CPA->getDiscriminator()));
     }
 
-    if (isa<ConstantPointerNull>(C)) {
-      unsigned AS = V->getType()->getPointerAddressSpace();
-      return DAG.getConstant(0, getCurSDLoc(),
-                             TLI.getPointerTy(DAG.getDataLayout(), AS));
-    }
+    if (isa<ConstantPointerNull>(C))
+      return DAG.getConstant(0, getCurSDLoc(), VT);
 
     if (match(C, m_VScale()))
       return DAG.getVScale(getCurSDLoc(), VT, APInt(VT.getSizeInBits(), 1));