fixup! [DAGCombine] Fix an incorrect folding of extract_subvector

Author: mshockwave

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

@@ -26018,12 +26018,12 @@ SDValue DAGCombiner::visitEXTRACT_SUBVECTOR(SDNode *N) {
   // Combine an extract of an extract into a single extract_subvector.
   // ext (ext X, C), 0 --> ext X, C
   if (ExtIdx == 0 && V.getOpcode() == ISD::EXTRACT_SUBVECTOR && V.hasOneUse()) {
-    if (TLI.isExtractSubvectorCheap(NVT, V.getOperand(0).getValueType(),
+    // The index has to be a multiple of the new result type's known minimum
+    // vector length.
+    if (V.getConstantOperandVal(1) % NVT.getVectorMinNumElements() == 0 &&
+        TLI.isExtractSubvectorCheap(NVT, V.getOperand(0).getValueType(),
                                     V.getConstantOperandVal(1)) &&
-        TLI.isOperationLegalOrCustom(ISD::EXTRACT_SUBVECTOR, NVT) &&
-        // The index has to be a multiple of the new result type's known minimum
-        // vector length.
-        V.getConstantOperandVal(1) % NVT.getVectorMinNumElements() == 0) {
+        TLI.isOperationLegalOrCustom(ISD::EXTRACT_SUBVECTOR, NVT)) {
       return DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, NVT, V.getOperand(0),
                          V.getOperand(1));
     }