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[CIR] Backport VecSplatOp simplifier #1704

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Merged
merged 1 commit into from
Jun 23, 2025
Merged

[CIR] Backport VecSplatOp simplifier #1704

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30 changes: 28 additions & 2 deletions clang/lib/CIR/Dialect/Transforms/CIRSimplify.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -141,6 +141,31 @@ struct SimplifySelect : public OpRewritePattern<SelectOp> {
}
};

struct SimplifyVecSplat : public OpRewritePattern<VecSplatOp> {
using OpRewritePattern<VecSplatOp>::OpRewritePattern;
LogicalResult matchAndRewrite(VecSplatOp op,
PatternRewriter &rewriter) const override {
mlir::Value splatValue = op.getValue();
auto constant =
mlir::dyn_cast_if_present<cir::ConstantOp>(splatValue.getDefiningOp());
if (!constant)
return mlir::failure();

auto value = constant.getValue();
if (!mlir::isa_and_nonnull<cir::IntAttr>(value) &&
!mlir::isa_and_nonnull<cir::FPAttr>(value))
return mlir::failure();

cir::VectorType resultType = op.getResult().getType();
SmallVector<mlir::Attribute, 16> elements(resultType.getSize(), value);
auto constVecAttr = cir::ConstVectorAttr::get(
resultType, mlir::ArrayAttr::get(getContext(), elements));

rewriter.replaceOpWithNewOp<cir::ConstantOp>(op, constVecAttr);
return mlir::success();
}
};

//===----------------------------------------------------------------------===//
// CIRSimplifyPass
//===----------------------------------------------------------------------===//
Expand All @@ -155,7 +180,8 @@ void populateMergeCleanupPatterns(RewritePatternSet &patterns) {
// clang-format off
patterns.add<
SimplifyTernary,
SimplifySelect
SimplifySelect,
SimplifyVecSplat
>(patterns.getContext());
// clang-format on
}
Expand All @@ -168,7 +194,7 @@ void CIRSimplifyPass::runOnOperation() {
// Collect operations to apply patterns.
llvm::SmallVector<Operation *, 16> ops;
getOperation()->walk([&](Operation *op) {
if (isa<TernaryOp, SelectOp>(op))
if (isa<TernaryOp, SelectOp, VecSplatOp>(op))
ops.push_back(op);
});

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16 changes: 16 additions & 0 deletions clang/test/CIR/Transforms/vector-splat.cir
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Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
// RUN: cir-opt %s -cir-simplify -o - | FileCheck %s

!s32i = !cir.int<s, 32>

module {
cir.func @fold_splat_vector_op_test() -> !cir.vector<!s32i x 4> {
%v = cir.const #cir.int<3> : !s32i
%vec = cir.vec.splat %v : !s32i, !cir.vector<!s32i x 4>
cir.return %vec : !cir.vector<!s32i x 4>
}

// CHECK: cir.func @fold_splat_vector_op_test() -> !cir.vector<!s32i x 4> {
// CHECK-NEXT: %0 = cir.const #cir.const_vector<[#cir.int<3> : !s32i, #cir.int<3> : !s32i,
// CHECK-SAME: #cir.int<3> : !s32i, #cir.int<3> : !s32i]> : !cir.vector<!s32i x 4>
// CHECK-NEXT: cir.return %0 : !cir.vector<!s32i x 4>
}
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