[Mlir-commits] [mlir] [mlir][spirv][vector] Support converting vector.from_elements to SPIR-V (PR #118540)

[Jakub Kuderski]

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@@ -220,6 +220,34 @@ struct VectorFmaOpConvert final : public OpConversionPattern<vector::FMAOp> {
   }
 };
 
+struct VectorFromElementsOpConvert final
+    : public OpConversionPattern<vector::FromElementsOp> {
+  using OpConversionPattern::OpConversionPattern;
+
+  LogicalResult
+  matchAndRewrite(vector::FromElementsOp op, OpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    Type resultType = getTypeConverter()->convertType(op.getType());
+    auto elements = op.getElements();
+    if (!resultType)
+      return failure();
+    if (isa<spirv::ScalarType>(resultType)) {
+      // In the case with a single scalar operand / single-element result,
+      // pass through the scalar.
+      rewriter.replaceOp(op, elements[0]);
+      return success();
+    } else if (cast<VectorType>(resultType).getRank() == 1) {
+      // SPIRVTypeConverter rejects vectors with rank > 1, so the
+      // multi-dimensional vector.from_elements cases do not need to be handled,
+      // only a simple flat vector.
+      rewriter.replaceOpWithNewOp<spirv::CompositeConstructOp>(op, resultType,
+                                                               elements);
+      return success();
+    }
+    return failure();
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kuhar wrote:

I don't think we need this `return` -- this code seems unreachable to me

https://github.com/llvm/llvm-project/pull/118540