================
@@ -1773,6 +1774,38 @@ mlir::LogicalResult
CIRToLLVMVecInsertOpLowering::matchAndRewrite(
return mlir::success();
}
+mlir::LogicalResult CIRToLLVMVecSplatOpLowering::matchAndRewrite(
+ cir::VecSplatOp op, OpAdaptor adaptor,
+ mlir::ConversionPatternRewriter &rewriter) const {
+ // Vector splat can be implemented with an `insertelement` and a
+ // `shufflevector`, which is better than an `insertelement` for each
+ // element in the vector. Start with an undef vector. Insert the value into
+ // the first element. Then use a `shufflevector` with a mask of all 0 to
+ // fill out the entire vector with that value.
+ const auto vecTy = mlir::cast<cir::VectorType>(op.getType());
+ const mlir::Type llvmTy = typeConverter->convertType(vecTy);
+ const mlir::Location loc = op.getLoc();
+ const mlir::Value poison = rewriter.create<mlir::LLVM::PoisonOp>(loc,
llvmTy);
+
+ const mlir::Value elementValue = adaptor.getValue();
+ if (mlir::isa<mlir::LLVM::PoisonOp>(elementValue.getDefiningOp())) {
+ // If the splat value is poison, then we can just use poison value
+ // for the entire vector.
+ rewriter.replaceOp(op, poison);
+ return mlir::success();
+ }
+
+ const mlir::Value indexValue =
+ rewriter.create<mlir::LLVM::ConstantOp>(loc, rewriter.getI64Type(), 0);
+ const mlir::Value oneElement = rewriter.create<mlir::LLVM::InsertElementOp>(
+ loc, poison, elementValue, indexValue);
+ const SmallVector<int32_t> zeroValues(vecTy.getSize(), 0);
+ const mlir::Value shuffled = rewriter.create<mlir::LLVM::ShuffleVectorOp>(
+ loc, oneElement, poison, zeroValues);
+ rewriter.replaceOp(op, shuffled);
----------------
xlauko wrote:
```suggestion
rewriter. replaceOpWithNewOp<mlir::LLVM::ShuffleVectorOp>(op, oneElement,
poison, zeroValues);
```
https://github.com/llvm/llvm-project/pull/139827
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