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[mlir][AMDGPU] Infer canonical layouts for fat_raw_buffer_cast resetOffset #149867

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Merged
krzysz00 merged 1 commit into from
Jul 21, 2025
Merged

[mlir][AMDGPU] Infer canonical layouts for fat_raw_buffer_cast resetOffset #149867

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18 changes: 17 additions & 1 deletion mlir/lib/Dialect/AMDGPU/IR/AMDGPUDialect.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
#include "mlir/Dialect/GPU/IR/GPUDialect.h"
#include "mlir/Dialect/LLVMIR/ROCDLDialect.h"
#include "mlir/Dialect/MemRef/Utils/MemRefUtils.h"
#include "mlir/Dialect/Utils/IndexingUtils.h"
#include "mlir/IR/Builders.h"
#include "mlir/IR/BuiltinTypes.h"
#include "mlir/IR/Diagnostics.h"
Expand Down Expand Up @@ -89,7 +90,22 @@ static FailureOr<MemRefType> getFatRawBufferTypeLike(MemRefType source,
auto stridedLayout = dyn_cast<StridedLayoutAttr>(layout);
if (!stridedLayout)
return failure();
mb.setLayout(StridedLayoutAttr::get(ctx, 0, stridedLayout.getStrides()));
MemRefLayoutAttrInterface newLayout =
StridedLayoutAttr::get(ctx, 0, stridedLayout.getStrides());
// Special case: if resetting the offset causes the strided layout to become
// the identity layout, then reset to the identity layout.
// TODO: this'll get a lot simpler when we have the contiguous layout.
SmallVector<int64_t> stridesIfIdentity;
if (source.hasStaticShape()) {
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@lialan lialan Jul 21, 2025

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What about making a utility function something likeisIdentity for this? Looks useful.

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@krzysz00 krzysz00 Jul 21, 2025

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Agreed - in my to-be-split contiguous layouts PR, this was something along the lines of MemRefLayoutAttrInterface StridedLayoutAttr::getCanonical(sizes, strides, offset);, but that's future work / a branch that needs to be rescued.

stridesIfIdentity = computeSuffixProduct(source.getShape());
} else if (source.getRank() <= 1) {
stridesIfIdentity = SmallVector<int64_t>(source.getRank(), 1);
}
if (stridesIfIdentity == stridedLayout.getStrides()) {
newLayout = AffineMapAttr::get(
AffineMap::getMultiDimIdentityMap(source.getRank(), ctx));
}
mb.setLayout(newLayout);
}
return (MemRefType)(mb);
}
Expand Down
6 changes: 3 additions & 3 deletions mlir/test/Conversion/AMDGPUToROCDL/amdgpu-to-rocdl.mlir
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Expand Up @@ -68,7 +68,7 @@ func.func @fat_raw_buffer_cast_dyn_size_offset(%buf: memref<?xi32, strided<[1],
}

// CHECK-LABEL: func @fat_raw_buffer_cast_reset_offset
func.func @fat_raw_buffer_cast_reset_offset(%buf: memref<?xi32, strided<[1], offset: ?>, #gpu_global_addrspace>) -> memref<?xi32, strided<[1]>, #amdgpu.address_space<fat_raw_buffer>> {
func.func @fat_raw_buffer_cast_reset_offset(%buf: memref<?xi32, strided<[1], offset: ?>, #gpu_global_addrspace>) -> memref<?xi32, #amdgpu.address_space<fat_raw_buffer>> {
// CHECK: %[[desc:.*]] = builtin.unrealized_conversion_cast %{{.*}} : memref<?xi32, strided<[1], offset: ?>, 1> to !llvm.struct<(ptr<1>, ptr<1>, i64, array<1 x i64>, array<1 x i64>)>
// CHECK-DAG: %[[memRefPtr:.*]] = llvm.extractvalue %[[desc]][1]
// CHECK-DAG: %[[memRefOff:.*]] = llvm.extractvalue %[[desc]][2]
Expand All @@ -77,8 +77,8 @@ func.func @fat_raw_buffer_cast_reset_offset(%buf: memref<?xi32, strided<[1], off
// CHECK: %[[fatBuf:.*]] = rocdl.make.buffer.rsrc %[[basePtr]], %{{.*}}, %{{.*}}, %{{.*}}
// CHECK: llvm.insertvalue %[[fatBuf]], %{{.*}}[1]
// CHECK: llvm.insertvalue %[[zeroOff]], %{{.*}}[2]
%ret = amdgpu.fat_raw_buffer_cast %buf resetOffset : memref<?xi32, strided<[1], offset: ?>, #gpu_global_addrspace> to memref<?xi32, strided<[1]>, #amdgpu.address_space<fat_raw_buffer>>
return %ret : memref<?xi32, strided<[1]>, #amdgpu.address_space<fat_raw_buffer>>
%ret = amdgpu.fat_raw_buffer_cast %buf resetOffset : memref<?xi32, strided<[1], offset: ?>, #gpu_global_addrspace> to memref<?xi32, #amdgpu.address_space<fat_raw_buffer>>
return %ret : memref<?xi32, #amdgpu.address_space<fat_raw_buffer>>
}

// CHECK-LABEL: func @fat_raw_buffer_cast_valid_bytes
Expand Down
50 changes: 47 additions & 3 deletions mlir/test/Dialect/AMDGPU/ops.mlir
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Expand Up @@ -360,10 +360,54 @@ func.func @fat_raw_buffer_cast_easy(%m: memref<8xi32>) -> memref<8xi32, #amdgpu.
// CHECK-SAME: cacheSwizzleStride(%{{[^)]*}})
// CHECK-SAME: boundsCheck(false)
// CHECK-SAME: resetOffset
func.func @fat_raw_buffer_cast(%m: memref<8xi32, strided<[1], offset: ?>>, %validBytes: i32, %cacheSwizzle: i14) -> memref<8xi32, strided<[1]>, #amdgpu.address_space<fat_raw_buffer>> {
func.func @fat_raw_buffer_cast(%m: memref<8xi32, strided<[1], offset: ?>>, %validBytes: i32, %cacheSwizzle: i14) -> memref<8xi32, #amdgpu.address_space<fat_raw_buffer>> {
%ret = amdgpu.fat_raw_buffer_cast %m validBytes(%validBytes) cacheSwizzleStride(%cacheSwizzle) boundsCheck(false) resetOffset
: memref<8xi32, strided<[1], offset: ?>> to memref<8xi32, strided<[1]>, #amdgpu.address_space<fat_raw_buffer>>
func.return %ret : memref<8xi32, strided<[1]>, #amdgpu.address_space<fat_raw_buffer>>
: memref<8xi32, strided<[1], offset: ?>> to memref<8xi32, #amdgpu.address_space<fat_raw_buffer>>
func.return %ret : memref<8xi32, #amdgpu.address_space<fat_raw_buffer>>
}

// CHECK-LABEL: func @fat_raw_buffer_cast_dynamic_1d_reset_offset
// CHECK: amdgpu.fat_raw_buffer_cast
func.func @fat_raw_buffer_cast_dynamic_1d_reset_offset(%m: memref<?xi32, strided<[1], offset: ?>>) -> memref<?xi32, #amdgpu.address_space<fat_raw_buffer>> {
%ret = amdgpu.fat_raw_buffer_cast %m resetOffset
: memref<?xi32, strided<[1], offset: ?>> to memref<?xi32, #amdgpu.address_space<fat_raw_buffer>>
func.return %ret : memref<?xi32, #amdgpu.address_space<fat_raw_buffer>>
}

// CHECK-LABEL: func @fat_raw_buffer_cast_dynamic_0d_reset_offset
// CHECK: %[[ret:.+]] = amdgpu.fat_raw_buffer_cast
// CHECK: return %[[ret]]
func.func @fat_raw_buffer_cast_dynamic_0d_reset_offset(%m: memref<i32, strided<[], offset: ?>>) -> memref<i32, #amdgpu.address_space<fat_raw_buffer>> {
%ret = amdgpu.fat_raw_buffer_cast %m resetOffset
: memref<i32, strided<[], offset: ?>> to memref<i32, #amdgpu.address_space<fat_raw_buffer>>
func.return %ret : memref<i32, #amdgpu.address_space<fat_raw_buffer>>
}

// CHECK-LABEL: func @fat_raw_buffer_cast_static_shape_2d_reset_offset
// CHECK: %[[ret:.+]] = amdgpu.fat_raw_buffer_cast
// CHECK: return %[[ret]]
func.func @fat_raw_buffer_cast_static_shape_2d_reset_offset(%m: memref<4x4xi32, strided<[4, 1], offset: ?>>) -> memref<4x4xi32, #amdgpu.address_space<fat_raw_buffer>> {
%ret = amdgpu.fat_raw_buffer_cast %m resetOffset
: memref<4x4xi32, strided<[4, 1], offset: ?>> to memref<4x4xi32, #amdgpu.address_space<fat_raw_buffer>>
func.return %ret : memref<4x4xi32, #amdgpu.address_space<fat_raw_buffer>>
}

// CHECK-LABEL: func @fat_raw_buffer_cast_dynamic_2d_reset_offset
// CHECK: %[[ret:.+]] = amdgpu.fat_raw_buffer_cast
// CHECK: return %[[ret]]
func.func @fat_raw_buffer_cast_dynamic_2d_reset_offset(%m: memref<?x?xi32, strided<[?, 1], offset: ?>>) -> memref<?x?xi32, strided<[?, 1]>, #amdgpu.address_space<fat_raw_buffer>> {
%ret = amdgpu.fat_raw_buffer_cast %m resetOffset
: memref<?x?xi32, strided<[?, 1], offset: ?>> to memref<?x?xi32, strided<[?, 1]>, #amdgpu.address_space<fat_raw_buffer>>
func.return %ret : memref<?x?xi32, strided<[?, 1]>, #amdgpu.address_space<fat_raw_buffer>>
}

// CHECK-LABEL: func @fat_raw_buffer_cast_noncontiguous_2d_reset_offset
// CHECK: %[[ret:.+]] = amdgpu.fat_raw_buffer_cast
// CHECK: return %[[ret]]
func.func @fat_raw_buffer_cast_noncontiguous_2d_reset_offset(%m: memref<4x4xi32, strided<[8, 1], offset: ?>>) -> memref<4x4xi32, strided<[8, 1]>, #amdgpu.address_space<fat_raw_buffer>> {
%ret = amdgpu.fat_raw_buffer_cast %m resetOffset
: memref<4x4xi32, strided<[8, 1], offset: ?>> to memref<4x4xi32, strided<[8, 1]>, #amdgpu.address_space<fat_raw_buffer>>
func.return %ret : memref<4x4xi32, strided<[8, 1]>, #amdgpu.address_space<fat_raw_buffer>>
}

// CHECK-LABEL: func @raw_buffer_load_f32_from_rank_1
Expand Down
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