[Mlir-commits] [mlir] [MLIR][Conversion] Vector to LLVM: Remove unneeded vector shuffle (PR #162946)

[Sang Ik Lee]

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@@ -1723,12 +1723,17 @@ struct VectorBroadcastScalarToLowRankLowering
       return success();
     }
 
-    // For 1-d vector, we additionally do a `vectorshuffle`.
     auto v =
         LLVM::InsertElementOp::create(rewriter, broadcast.getLoc(), vectorType,
                                       poison, adaptor.getSource(), zero);
 
+    // For 1-d vector, if vector width > 1, we additionally do a
+    // `vector shuffle`
     int64_t width = cast<VectorType>(broadcast.getType()).getDimSize(0);
+    if (width == 1) {
+      rewriter.replaceOp(broadcast, v);
+      return success();
+    }
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silee2 wrote:

Added folding pattern for llvm.shufflevector and using createOrFold.

https://github.com/llvm/llvm-project/pull/162946