[mlir] Only attempt to vectorize conv if conv.

Avoids hitting assertions due to unsupported convolution patterns.

See iree-org/iree#15207 (comment)

Author: jpienaar

mlir/lib/Dialect/Linalg/Transforms/Vectorization.cpp

@@ -1693,11 +1693,16 @@ LogicalResult mlir::linalg::vectorize(RewriterBase &rewriter, Operation *op,
           .Case<linalg::LinalgOp>([&](auto linalgOp) {
             // TODO: isaConvolutionOpInterface that can also infer from generic
             // features. Will require stride/dilation attributes inference.
-            FailureOr<Operation *> convOr =
-                vectorizeConvolution(rewriter, linalgOp);
-            if (succeeded(convOr)) {
-              llvm::append_range(results, (*convOr)->getResults());
-              return success();
+            if (isa<ConvolutionOpInterface>(linalgOp.getOperation())) {
+              FailureOr<Operation *> convOr =
+                  vectorizeConvolution(rewriter, linalgOp);
+              if (succeeded(convOr)) {
+                llvm::append_range(results, (*convOr)->getResults());
+                return success();
+              }
+
+              LDBG("Unsupported convolution can't be vectorized.\n");
+              return failure();
             }
 
             LDBG("Vectorize generic by broadcasting to the canonical vector "