[X86][SSE] Combine EXTRACT_VECTOR_ELT with combineExtractWithShuffle before XFormVExtractWithShuffleIntoLoad

combineExtractWithShuffle can handle more complex shuffles/bitcasts than we can with the equivalent code in XFormVExtractWithShuffleIntoLoad.

Mainly a compile time improvement now (combineExtractWithShuffle combines will have always failed late on inside XFormVExtractWithShuffleIntoLoad), and will let us merge combineExtractVectorElt_SSE in a future commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317481 91177308-0d34-0410-b5e6-96231b3b80d8

Author: RKSimon

lib/Target/X86/X86ISelLowering.cpp

@@ -30485,10 +30485,10 @@ static SDValue combineExtractWithShuffle(SDNode *N, SelectionDAG &DAG,
 static SDValue combineExtractVectorElt(SDNode *N, SelectionDAG &DAG,
                                        TargetLowering::DAGCombinerInfo &DCI,
                                        const X86Subtarget &Subtarget) {
-  if (SDValue NewOp = XFormVExtractWithShuffleIntoLoad(N, DAG, DCI))
+  if (SDValue NewOp = combineExtractWithShuffle(N, DAG, DCI, Subtarget))
     return NewOp;
 
-  if (SDValue NewOp = combineExtractWithShuffle(N, DAG, DCI, Subtarget))
+  if (SDValue NewOp = XFormVExtractWithShuffleIntoLoad(N, DAG, DCI))
     return NewOp;
 
   SDValue InputVector = N->getOperand(0);