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[MLIR] Add folding constants canonicalization for mlir::index::AddOp. #111084

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Merged
merged 3 commits into from
Oct 22, 2024
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[MLIR] Add folding constants canonicalization for mlir::index::AddOp. #111084

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8f90d38
Add folding constants canonicalization for mlir::index::AddOp.
weiweichen Oct 4, 2024
d1725fa
Merge branch 'main' of https://github.com/llvm/llvm-project into weiw…
weiweichen Oct 8, 2024
c755012
Address review comments.
weiweichen Oct 8, 2024
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2 changes: 2 additions & 0 deletions mlir/include/mlir/Dialect/Index/IR/IndexOps.td
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Expand Up @@ -56,6 +56,8 @@ def Index_AddOp : IndexBinaryOp<"add", [Commutative, Pure]> {
%c = index.add %a, %b
```
}];

let hasCanonicalizeMethod = 1;
}

//===----------------------------------------------------------------------===//
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22 changes: 22 additions & 0 deletions mlir/lib/Dialect/Index/IR/IndexOps.cpp
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Expand Up @@ -136,6 +136,28 @@ OpFoldResult AddOp::fold(FoldAdaptor adaptor) {

return {};
}
/// Canonicalize
/// ` x = v + c1; y = x + c2` to `x = v + (c1 + c2)`
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This is the only permutation of the pattern that you actually need to implement. The canonicalizer will make sure that constants for commutative ops are always on the RHS.

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oh, good to know, PR updated!

LogicalResult AddOp::canonicalize(AddOp op, PatternRewriter &rewriter) {
IntegerAttr c1, c2;
if (!mlir::matchPattern(op.getRhs(), mlir::m_Constant(&c1)))
return rewriter.notifyMatchFailure(op.getLoc(), "RHS is not a constant");

auto add = op.getLhs().getDefiningOp<mlir::index::AddOp>();
if (!add)
return rewriter.notifyMatchFailure(op.getLoc(), "LHS is not a add");

if (!mlir::matchPattern(add.getRhs(), mlir::m_Constant(&c2)))
return rewriter.notifyMatchFailure(op.getLoc(), "RHS is not a constant");

auto c = rewriter.create<mlir::index::ConstantOp>(op->getLoc(),
c1.getInt() + c2.getInt());
auto newAdd =
rewriter.create<mlir::index::AddOp>(op->getLoc(), add.getLhs(), c);

rewriter.replaceOp(op, newAdd);
return success();
}

//===----------------------------------------------------------------------===//
// SubOp
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13 changes: 13 additions & 0 deletions mlir/test/Dialect/Index/index-canonicalize.mlir
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Expand Up @@ -32,6 +32,19 @@ func.func @add_overflow() -> (index, index) {
return %2, %3 : index, index
}

// CHECK-LABEL: @add
func.func @add_fold_constants(%arg: index) -> (index) {
%0 = index.constant 1
%1 = index.constant 2
%2 = index.add %arg, %0
%3 = index.add %2, %1

// CHECK-DAG: [[C3:%.*]] = index.constant 3
// CHECK-DAG: [[V0:%.*]] = index.add %arg0, [[C3]]
// CHECK: return [[V0]]
return %3 : index
}

// CHECK-LABEL: @sub
func.func @sub() -> index {
%0 = index.constant -2000000000
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