Remove unnnecessary node duplication

Author: chrisjbris

llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp

@@ -735,7 +735,7 @@ static bool hasSourceMods(const SDNode *N) {
   case ISD::INLINEASM:
   case ISD::INLINEASM_BR:
   case AMDGPUISD::DIV_SCALE:
-  case ISD::INTRINSIC_W_CHAIN:
+  case ISD::INTRINSIC_W_CHAIN: 
 
   // TODO: Should really be looking at the users of the bitcast. These are
   // problematic because bitcasts are used to legalize all stores to integer
@@ -4086,9 +4086,8 @@ SDValue AMDGPUTargetLowering::performShlCombine(SDNode *N,
                                      LHSAND, Zero);
             SDValue Hi =
                 DAG.getNode(ISD::EXTRACT_VECTOR_ELT, SL, MVT::i32, LHSAND, One);
-            SDValue AndMask = DAG.getConstant(0x1f, SL, MVT::i32);
-            SDValue LoAnd = DAG.getNode(ISD::AND, SL, MVT::i32, Lo, AndMask);
-            SDValue HiAnd = DAG.getNode(ISD::AND, SL, MVT::i32, Hi, AndMask);
+            SDValue LoAnd = DAG.getNode(ISD::AND, SL, MVT::i32, Lo, RHSAND->getOperand(0));
+            SDValue HiAnd = DAG.getNode(ISD::AND, SL, MVT::i32, Hi, RHSAND->getOperand(0));
             SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SL, MVT::i32, LHS);
             if (AndIndex == 0 || AndIndex == 1)
               return DAG.getNode(ISD::SHL, SL, MVT::i32, Trunc,