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[mlir][affine] Add folders for delinearize_index and linearize_index #115766

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Merged
merged 1 commit into from
Nov 13, 2024
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[mlir][affine] Add folders for delinearize_index and linearize_index #115766

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2 changes: 2 additions & 0 deletions mlir/include/mlir/Dialect/Affine/IR/AffineOps.td
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Original file line number Diff line number Diff line change
Expand Up @@ -1110,6 +1110,7 @@ def AffineDelinearizeIndexOp : Affine_Op<"delinearize_index",
}];

let hasVerifier = 1;
let hasFolder = 1;
let hasCanonicalizer = 1;
}

Expand Down Expand Up @@ -1179,6 +1180,7 @@ def AffineLinearizeIndexOp : Affine_Op<"linearize_index",
}];

let hasVerifier = 1;
let hasFolder = 1;
let hasCanonicalizer = 1;
}

Expand Down
70 changes: 69 additions & 1 deletion mlir/lib/Dialect/Affine/IR/AffineOps.cpp
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Expand Up @@ -4556,6 +4556,26 @@ LogicalResult AffineDelinearizeIndexOp::verify() {
return success();
}

LogicalResult
AffineDelinearizeIndexOp::fold(FoldAdaptor adaptor,
SmallVectorImpl<OpFoldResult> &result) {
if (adaptor.getLinearIndex() == nullptr)
return failure();

if (!adaptor.getDynamicBasis().empty())
return failure();

int64_t highPart = cast<IntegerAttr>(adaptor.getLinearIndex()).getInt();
Type attrType = getLinearIndex().getType();
for (int64_t modulus : llvm::reverse(getStaticBasis().drop_front())) {
result.push_back(IntegerAttr::get(attrType, llvm::mod(highPart, modulus)));
highPart = llvm::divideFloorSigned(highPart, modulus);
}
result.push_back(IntegerAttr::get(attrType, highPart));
std::reverse(result.begin(), result.end());
return success();
}

namespace {

// Drops delinearization indices that correspond to unit-extent basis
Expand Down Expand Up @@ -4715,6 +4735,26 @@ LogicalResult AffineLinearizeIndexOp::verify() {
return success();
}

OpFoldResult AffineLinearizeIndexOp::fold(FoldAdaptor adaptor) {
if (llvm::any_of(adaptor.getMultiIndex(),
[](Attribute a) { return a == nullptr; }))
return nullptr;

if (!adaptor.getDynamicBasis().empty())
return nullptr;

int64_t result = 0;
int64_t stride = 1;
for (auto [indexAttr, length] :
llvm::zip_equal(llvm::reverse(adaptor.getMultiIndex()),
llvm::reverse(getStaticBasis()))) {
result = result + cast<IntegerAttr>(indexAttr).getInt() * stride;
stride = stride * length;
}

return IntegerAttr::get(getResult().getType(), result);
}

namespace {
/// Rewrite `affine.linearize_index disjoint [%...a, %x, %...b] by (%...c, 1,
/// %...d)` to `affine.linearize_index disjoint [%...a, %...b] by (%...c,
Expand Down Expand Up @@ -4820,11 +4860,39 @@ struct CancelLinearizeOfDelinearizeExact final
return success();
}
};

/// Strip leading zero from affine.linearize_index.
///
/// `affine.linearize_index [%c0, ...a] by (%x, ...b)` can be rewritten
/// to `affine.linearize_index [...a] by (...b)` in all cases.
struct DropLinearizeLeadingZero final
: OpRewritePattern<affine::AffineLinearizeIndexOp> {
using OpRewritePattern::OpRewritePattern;

LogicalResult matchAndRewrite(affine::AffineLinearizeIndexOp op,
PatternRewriter &rewriter) const override {
Value leadingIdx = op.getMultiIndex().front();
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IIUC you should be able to drop any zero-value basis (and the corresponding index) right?

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This is

%0 = affine.linearize_index [%c0, %x, %y] by (A, B, C)

going to

%0 = affine.linearize_index [%x, %y] by (B, C)

We can't do

%0 = affine.linearize_index [%x, %c0, %y] by (A, B, C)

to

%0 = affine.linearize_index [%x, %y] by (A, C)

since that has an %x * C term and not a %x * BC term.

Whether or not canonicalizing that to

%0 = affine.linearize_index [%x, %y] (A, BC)

is profitable is something I'm not sure about yet.

(We definitely can't drop trailing zeroes, since they'd be used to express %y * C-type operations)

if (!matchPattern(leadingIdx, m_Zero()))
return failure();

if (op.getMultiIndex().size() == 1) {
rewriter.replaceOp(op, leadingIdx);
return success();
}

SmallVector<OpFoldResult> mixedBasis = op.getMixedBasis();
rewriter.replaceOpWithNewOp<affine::AffineLinearizeIndexOp>(
op, op.getMultiIndex().drop_front(),
ArrayRef<OpFoldResult>(mixedBasis).drop_front(), op.getDisjoint());
return success();
}
};
} // namespace

void affine::AffineLinearizeIndexOp::getCanonicalizationPatterns(
RewritePatternSet &patterns, MLIRContext *context) {
patterns.add<CancelLinearizeOfDelinearizeExact, DropLinearizeOneBasisElement,
patterns.add<CancelLinearizeOfDelinearizeExact, DropLinearizeLeadingZero,
DropLinearizeOneBasisElement,
DropLinearizeUnitComponentsIfDisjointOrZero>(context);
}

Expand Down
80 changes: 80 additions & 0 deletions mlir/test/Dialect/Affine/canonicalize.mlir
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Original file line number Diff line number Diff line change
Expand Up @@ -1469,6 +1469,45 @@ func.func @prefetch_canonicalize(%arg0: memref<512xf32>) -> () {

// -----

// CHECK-LABEL: @delinearize_fold_constant
// CHECK-DAG: %[[C1:.+]] = arith.constant 1 : index
// CHECK-DAG: %[[C2:.+]] = arith.constant 2 : index
// CHECK-NOT: affine.delinearize_index
// CHECK: return %[[C1]], %[[C1]], %[[C2]]
func.func @delinearize_fold_constant() -> (index, index, index) {
%c22 = arith.constant 22 : index
%0:3 = affine.delinearize_index %c22 into (2, 3, 5) : index, index, index
return %0#0, %0#1, %0#2 : index, index, index
}

// -----

// CHECK-LABEL: @delinearize_fold_negative_constant
// CHECK-DAG: %[[C_2:.+]] = arith.constant -2 : index
// CHECK-DAG: %[[C1:.+]] = arith.constant 1 : index
// CHECK-DAG: %[[C3:.+]] = arith.constant 3 : index
// CHECK-NOT: affine.delinearize_index
// CHECK: return %[[C_2]], %[[C1]], %[[C3]]
func.func @delinearize_fold_negative_constant() -> (index, index, index) {
%c_22 = arith.constant -22 : index
%0:3 = affine.delinearize_index %c_22 into (2, 3, 5) : index, index, index
return %0#0, %0#1, %0#2 : index, index, index
}

// -----

// CHECK-LABEL: @delinearize_dont_fold_constant_dynamic_basis
// CHECK-DAG: %[[C22:.+]] = arith.constant 22 : index
// CHECK: %[[RET:.+]]:3 = affine.delinearize_index %[[C22]]
// CHECK: return %[[RET]]#0, %[[RET]]#1, %[[RET]]#2
func.func @delinearize_dont_fold_constant_dynamic_basis(%arg0: index) -> (index, index, index) {
%c22 = arith.constant 22 : index
%0:3 = affine.delinearize_index %c22 into (2, %arg0, 5) : index, index, index
return %0#0, %0#1, %0#2 : index, index, index
}

// -----

func.func @drop_unit_basis_in_delinearize(%arg0 : index, %arg1 : index, %arg2 : index) ->
(index, index, index, index, index, index) {
%c1 = arith.constant 1 : index
Expand Down Expand Up @@ -1535,6 +1574,33 @@ func.func @delinearize_non_loop_like(%arg0: memref<?xi32>, %i : index) -> index

// -----

// CHECK-LABEL: @linearize_fold_constants
// CHECK-DAG: %[[C22:.+]] = arith.constant 22 : index
// CHECK-NOT: affine.linearize
// CHECK: return %[[C22]]
func.func @linearize_fold_constants() -> index {
%c2 = arith.constant 2 : index
%c1 = arith.constant 1 : index

%ret = affine.linearize_index [%c1, %c1, %c2] by (2, 3, 5) : index
return %ret : index
}

// -----

// CHECK-LABEL: @linearize_dont_fold_dynamic_basis
// CHECK: %[[RET:.+]] = affine.linearize_index
// CHECK: return %[[RET]]
func.func @linearize_dont_fold_dynamic_basis(%arg0: index) -> index {
%c2 = arith.constant 2 : index
%c1 = arith.constant 1 : index

%ret = affine.linearize_index [%c1, %c1, %c2] by (2, %arg0, 5) : index
return %ret : index
}

// -----

// CHECK-LABEL: func @cancel_delinearize_linearize_disjoint_exact(
// CHECK-SAME: %[[ARG0:[a-zA-Z0-9]+]]: index,
// CHECK-SAME: %[[ARG1:[a-zA-Z0-9]+]]: index,
Expand Down Expand Up @@ -1676,3 +1742,17 @@ func.func @no_cancel_linearize_denearize_different_basis(%arg0: index, %arg1: in
%1 = affine.linearize_index [%0#0, %0#1, %0#2] by (%arg1, 8, %arg2) : index
return %1 : index
}

// -----

// CHECK-LABEL: func @affine_leading_zero(
// CHECK-SAME: %[[ARG0:[a-zA-Z0-9]+]]: index,
// CHECK-SAME: %[[ARG1:[a-zA-Z0-9]+]]: index)
// CHECK: %[[RET:.+]] = affine.linearize_index [%[[ARG0]], %[[ARG1]]] by (3, 5)
// CHECK: return %[[RET]]
func.func @affine_leading_zero(%arg0: index, %arg1: index) -> index {
%c0 = arith.constant 0 : index
%ret = affine.linearize_index [%c0, %arg0, %arg1] by (2, 3, 5) : index
return %ret : index
}

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