fixup! [mlir][vector] Fix emulation of "narrow" type vector.store

Incorporate comments from Alan

Author: banach-space

mlir/lib/Dialect/Vector/Transforms/VectorEmulateNarrowType.cpp

@@ -597,10 +597,9 @@ struct ConvertVectorStore final : OpConversionPattern<vector::StoreOp> {
     // corresponding index must be 0.
     // FIXME: There's no way to tell for dynamic shapes, so we should bail out.
     // However, that makes some tests fail, so we need to audit first.
+    auto trailingDim = op.getBase().getType().getShape().back();
     bool trailingDimsMatch =
-        ShapedType::isDynamic(op.getBase().getType().getShape().back())
-            ? true
-            : op.getBase().getType().getShape().back() == origElements;
+        ShapedType::isDynamic(trailingDim) || trailingDim == origElements;
 
     auto stridedMetadata =
         rewriter.create<memref::ExtractStridedMetadataOp>(loc, op.getBase());

mlir/test/Dialect/Vector/vector-emulate-narrow-type.mlir

@@ -442,6 +442,7 @@ func.func @vector_store_i4(%arg0: vector<8xi4>, %arg1: index, %arg2: index) {
 // FIXME: This example assumes that the store happens at a byte boundary, but
 // that's not guaranteed. Below is a counter-example with specific dimensions:
 //    vector.store %arg0, %0[0, 3] : memref<2x13xi4>, vector<8xi4>
+// TODO: Revisit post #136797
 
 func.func @vector_store_i4_dynamic(%arg0: vector<8xi4>, %arg1: index, %arg2: index, %arg3: index, %arg4: index) {
     %0 = memref.alloc(%arg1, %arg2) : memref<?x?xi4>