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[MLIR] Determine contiguousness of memrefs with a dynamic dimension #140872

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[MLIR] Determine contiguousness of memrefs with a dynamic dimension #140872

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a55d425
[MLIR] Determine contiguousness of memrefs with a dynamic dimension
momchil-velikov May 21, 2025
d6dd4e9
[fixup] Fix formatting
momchil-velikov May 21, 2025
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7 changes: 5 additions & 2 deletions mlir/lib/IR/BuiltinTypes.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -649,7 +649,10 @@ bool MemRefType::areTrailingDimsContiguous(int64_t n) {
if (!isLastDimUnitStride())
return false;

auto memrefShape = getShape().take_back(n);
if (n == 1)
return true;

auto memrefShape = getShape().take_back(n - 1);
if (ShapedType::isDynamicShape(memrefShape))
return false;

Expand All @@ -668,7 +671,7 @@ bool MemRefType::areTrailingDimsContiguous(int64_t n) {
// Check whether strides match "flattened" dims.
SmallVector<int64_t> flattenedDims;
auto dimProduct = 1;
for (auto dim : llvm::reverse(memrefShape.drop_front(1))) {
for (auto dim : llvm::reverse(memrefShape)) {
dimProduct *= dim;
flattenedDims.push_back(dimProduct);
}
Expand Down
90 changes: 81 additions & 9 deletions mlir/test/Dialect/Vector/vector-transfer-flatten.mlir
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Original file line number Diff line number Diff line change
Expand Up @@ -188,18 +188,20 @@ func.func @transfer_read_leading_dynamic_dims(

// -----

// One of the dims to be flattened is dynamic - not supported ATM.
// One of the dims to be flattened is dynamic and not the leftmost - not
// possible to reason whether the memref is contiguous as the dynamic dimension
// could be one and the corresponding stride could be arbitrary.

func.func @negative_transfer_read_dynamic_dim_to_flatten(
%idx_1: index,
%idx_2: index,
%mem: memref<1x?x4x6xi32>) -> vector<1x2x6xi32> {
%mem: memref<1x4x?x6xi32>) -> vector<1x2x6xi32> {

%c0 = arith.constant 0 : index
%c0_i32 = arith.constant 0 : i32
%res = vector.transfer_read %mem[%c0, %idx_1, %idx_2, %c0], %c0_i32 {
in_bounds = [true, true, true]
} : memref<1x?x4x6xi32>, vector<1x2x6xi32>
} : memref<1x4x?x6xi32>, vector<1x2x6xi32>
return %res : vector<1x2x6xi32>
}

Expand All @@ -212,6 +214,41 @@ func.func @negative_transfer_read_dynamic_dim_to_flatten(

// -----

// One of the dims to be flattened is dynamic and leftmost.

func.func @transfer_read_dynamic_leftmost_dim_to_flatten(
%idx_1: index,
%idx_2: index,
%mem: memref<1x?x4x6xi32>) -> vector<1x2x6xi32> {

%c0 = arith.constant 0 : index
%c0_i32 = arith.constant 0 : i32
%res = vector.transfer_read %mem[%c0, %idx_1, %idx_2, %c0], %c0_i32 {
in_bounds = [true, true, true]
} : memref<1x?x4x6xi32>, vector<1x2x6xi32>
return %res : vector<1x2x6xi32>
}

// CHECK-LABEL: func.func @transfer_read_dynamic_leftmost_dim_to_flatten
// CHECK-SAME: %[[IDX_1:arg0]]: index
// CHECK-SAME: %[[IDX_2:arg1]]: index
// CHECK-SAME: %[[MEM:arg2]]: memref<1x?x4x6xi32>
// CHECK-NEXT: %[[C0_I32:.+]] = arith.constant 0 : i32
// CHECK-NEXT: %[[C0:.+]] = arith.constant 0 : index
// CHECK-NEXT: %[[COLLAPSED:.+]] = memref.collapse_shape %[[MEM]] {{\[}}[0], [1, 2, 3]{{\]}}
// CHECK-SAME: : memref<1x?x4x6xi32> into memref<1x?xi32>
// CHECK-NEXT: %[[TMP:.+]] = affine.apply #map{{.*}}()[%[[IDX_1]], %[[IDX_2]]]
// CHECK-NEXT: %[[VEC1D:.+]] = vector.transfer_read %[[COLLAPSED]]
// CHECK-SAME: [%[[C0]], %[[TMP]]], %[[C0_I32]]
// CHECK-SAME: {in_bounds = [true]} : memref<1x?xi32>, vector<12xi32>
// CHECK-NEXT: %[[RES:.+]] = vector.shape_cast %[[VEC1D]] : vector<12xi32> to vector<1x2x6xi32>
// CHECK-NEXT: return %[[RES]] : vector<1x2x6xi32>

// CHECK-128B-LABEL: func @transfer_read_dynamic_leftmost_dim_to_flatten
// CHECK-128B-NOT: memref.collapse_shape

// -----

// The vector to be read represents a _non-contiguous_ slice of the input
// memref.

Expand Down Expand Up @@ -451,26 +488,61 @@ func.func @transfer_write_leading_dynamic_dims(

// -----

// One of the dims to be flattened is dynamic - not supported ATM.
// One of the dims to be flattened is dynamic and not leftmost.

func.func @negative_transfer_write_dynamic_to_flatten(
func.func @negative_transfer_write_dynamic_dim_to_flatten(
%idx_1: index,
%idx_2: index,
%vec : vector<1x2x6xi32>,
%mem: memref<1x?x4x6xi32>) {
%mem: memref<1x4x?x6xi32>) {

%c0 = arith.constant 0 : index
%c0_i32 = arith.constant 0 : i32
vector.transfer_write %vec, %mem[%c0, %idx_1, %idx_2, %c0] {in_bounds = [true, true, true]} :
vector<1x2x6xi32>, memref<1x?x4x6xi32>
vector<1x2x6xi32>, memref<1x4x?x6xi32>
return
}

// CHECK-LABEL: func.func @negative_transfer_write_dynamic_to_flatten
// CHECK-LABEL: func.func @negative_transfer_write_dynamic_dim_to_flatten
// CHECK-NOT: memref.collapse_shape
// CHECK-NOT: vector.shape_cast

// CHECK-128B-LABEL: func @negative_transfer_write_dynamic_to_flatten
// CHECK-128B-LABEL: func @negative_transfer_write_dynamic_dim_to_flatten
// CHECK-128B-NOT: memref.collapse_shape

// -----

// One of the dims to be flattened is dynamic and leftmost.

func.func @transfer_write_dynamic_leftmost_dim_to_flatten(
%idx_1: index,
%idx_2: index,
%vec : vector<1x2x6xi32>,
%mem: memref<1x?x4x6xi32>) {

%c0 = arith.constant 0 : index
%c0_i32 = arith.constant 0 : i32
vector.transfer_write %vec, %mem[%c0, %idx_1, %idx_2, %c0] {in_bounds = [true, true, true]} :
vector<1x2x6xi32>, memref<1x?x4x6xi32>
return
}

// CHECK-LABEL: func.func @transfer_write_dynamic_leftmost_dim_to_flatten
// CHECK-SAME: %[[IDX_1:arg0]]: index
// CHECK-SAME: %[[IDX_2:arg1]]: index
// CHECK-SAME: %[[VEC:arg2]]: vector<1x2x6xi32>,
// CHECK-SAME: %[[MEM:arg3]]: memref<1x?x4x6xi32>
// CHECK-NEXT: %[[C0:.+]] = arith.constant 0 : index
// CHECK-NEXT: %[[COLLAPSED:.+]] = memref.collapse_shape %[[MEM]] {{\[}}[0], [1, 2, 3]{{\]}}
// CHECK-SAME: : memref<1x?x4x6xi32> into memref<1x?xi32>
// CHECK-NEXT: %[[TMP:.+]] = affine.apply #map{{.*}}()[%[[IDX_1]], %[[IDX_2]]]
// CHECK-NEXT: %[[VEC1D:.+]] = vector.shape_cast %[[VEC]] : vector<1x2x6xi32> to vector<12xi32>
// CHECK-NEXT: vector.transfer_write %[[VEC1D]], %[[COLLAPSED]]
// CHECK-SAME: [%[[C0]], %[[TMP]]]
// CHECK-SAME: {in_bounds = [true]} : vector<12xi32>, memref<1x?xi32>
// CHECK-NEXT: return

// CHECK-128B-LABEL: func @transfer_write_dynamic_leftmost_dim_to_flatten
// CHECK-128B-NOT: memref.collapse_shape

// -----
Expand Down
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