refine comment

Author: Yang Bai

mlir/lib/Dialect/Vector/IR/VectorOps.cpp

@@ -2146,8 +2146,9 @@ OpFoldResult ExtractOp::fold(FoldAdaptor adaptor) {
     return getVector();
   if (auto res = foldPoisonSrcExtractOp(adaptor.getVector()))
     return res;
-  // Fold `arith.constant` indices into the `vector.extract` operation. Make
-  // sure that patterns requiring constant indices are added after this fold.
+  // Fold `arith.constant` indices into the `vector.extract` operation.
+  // Do not stop here as this fold may enable subsequent folds that require
+  // constant indices.
   SmallVector<Value> operands = {getVector()};
   auto inplaceFolded = extractInsertFoldConstantOp(*this, adaptor, operands);
 
@@ -3149,8 +3150,9 @@ OpFoldResult vector::InsertOp::fold(FoldAdaptor adaptor) {
   // (type mismatch).
   if (getNumIndices() == 0 && getValueToStoreType() == getType())
     return getValueToStore();
-  // Fold `arith.constant` indices into the `vector.insert` operation. Make
-  // sure that patterns requiring constant indices are added after this fold.
+  // Fold `arith.constant` indices into the `vector.insert` operation.
+  // Do not stop here as this fold may enable subsequent folds that require
+  // constant indices.
   SmallVector<Value> operands = {getValueToStore(), getDest()};
   auto inplaceFolded = extractInsertFoldConstantOp(*this, adaptor, operands);