[Mlir-commits] [mlir] [mlir][Linalg] Refine how broadcast dims are treated (PR #99015)
llvmlistbot at llvm.org
llvmlistbot at llvm.org
Tue Jul 16 03:30:56 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-mlir-linalg
@llvm/pr-subscribers-mlir
Author: Andrzej Warzyński (banach-space)
<details>
<summary>Changes</summary>
This PR fixes how broadcast dims (identified as "zero" results in
permutation maps) corresponding to a reduction iterator are vectorised
in the case of generic Ops. Here's an example:
```mlir
#map = affine_map<(d0, d1, d2, d3) -> (d0, d1, d2, d3)>
#map1 = affine_map<(d0, d1, d2, d3) -> (d0, d1, d2, 0)>
func.func @<!-- -->generic_with_reduction_and_broadcast(%arg0: tensor<1x12x197x197xf32>) -> (tensor<1x12x197x1xf32>) {
%0 = tensor.empty() : tensor<1x12x197x1xf32>
%1 = linalg.generic {indexing_maps = [#map, #map1],
iterator_types = ["parallel", "parallel", "parallel", "reduction"]}
ins(%arg0 : tensor<1x12x197x197xf32>)
outs(%0 : tensor<1x12x197x1xf32>) {
^bb0(%in: f32, %out: f32):
%818 = arith.addf %in, %out : f32
linalg.yield %818 : f32
} -> tensor<1x12x197x1xf32>
return %1 : tensor<1x12x197x1xf32>
}
```
This is a perfectly valid Generic Op, but currently triggers two issues
in the vectoriser. The root cause is this map:
```mlir
#map1 = affine_map<(d0, d1, d2, d3) -> (d0, d1, d2, 0)>
```
This map triggers an assert in `reindexIndexingMap` - this hook
incorrectly assumes that every result in the input map is a `dim`
expression and that there are no constants. That's not the case in this
example. `reindexIndexingMap` is extended to allow maps like the one
above. For now, only constant "zero" results are allowed. This can be
extended in the future once a good motivating example is available.
Separately, the permutation map highlighted above "breaks" mask
calculation (ATM masks are always computed, even in the presence of
static shapes). When applying the following permutation:
```mlir
(d0, d1, d2, d3) -> (d0, d1, d2, 0)
```
to these canonical shapes (corresponding to the example above):
```
(1, 12, 197, 197)
```
we end up with the following error:
```bash
error: vector types must have positive constant sizes but got 1, 12, 197, 0
```
The error makes sense and indicates that we should update the
permutation map above to:
```
(d0, d1, d2, d3) -> (d0, d1, d2)
```
This would correctly give the following vector type:
```
vector<1x12x197xi1>
```
Fixes #<!-- -->97247
---
Full diff: https://github.com/llvm/llvm-project/pull/99015.diff
5 Files Affected:
- (modified) mlir/include/mlir/IR/AffineMap.h (+4)
- (modified) mlir/lib/Dialect/Linalg/Transforms/Vectorization.cpp (+16-2)
- (modified) mlir/lib/IR/AffineMap.cpp (+23)
- (modified) mlir/test/Dialect/Linalg/vectorization-with-patterns.mlir (+40)
- (modified) mlir/test/Dialect/Linalg/vectorization.mlir (+45)
``````````diff
diff --git a/mlir/include/mlir/IR/AffineMap.h b/mlir/include/mlir/IR/AffineMap.h
index 264c1c8308e78..866fe01e53665 100644
--- a/mlir/include/mlir/IR/AffineMap.h
+++ b/mlir/include/mlir/IR/AffineMap.h
@@ -346,6 +346,10 @@ class AffineMap {
/// returns the resulting values. `this` must be symbol-less.
SmallVector<int64_t, 4> compose(ArrayRef<int64_t> values) const;
+ size_t numOfZeroResults() const;
+
+ AffineMap dropZeros();
+
/// Returns true if the AffineMap represents a subset (i.e. a projection) of a
/// symbol-less permutation map. `allowZeroInResults` allows projected
/// permutation maps with constant zero result expressions.
diff --git a/mlir/lib/Dialect/Linalg/Transforms/Vectorization.cpp b/mlir/lib/Dialect/Linalg/Transforms/Vectorization.cpp
index a4c0508d0d8fa..288a05559e0b8 100644
--- a/mlir/lib/Dialect/Linalg/Transforms/Vectorization.cpp
+++ b/mlir/lib/Dialect/Linalg/Transforms/Vectorization.cpp
@@ -476,7 +476,7 @@ static AffineMap reindexIndexingMap(AffineMap map) {
assert(map.isProjectedPermutation(/*allowZeroInResults=*/true) &&
"expected projected permutation");
auto res = compressUnusedDims(map);
- assert(res.getNumDims() == res.getNumResults() &&
+ assert(res.getNumDims() == (res.getNumResults() - res.numOfZeroResults()) &&
"expected reindexed map with same number of dims and results");
return res;
}
@@ -629,7 +629,21 @@ static Value buildVectorWrite(RewriterBase &rewriter, Value value,
loc, value, outputOperand->get(), ValueRange{});
}
- write = state.maskOperation(rewriter, write, linalgOp, opOperandMap);
+ // The operand map may contain "zero" results, e.g.:
+ // (d0, d1, d2, d3) -> (d0, d1, d2, 0)
+ // When applied to canonical vector shapes like these:
+ // (1, 16, 16, 4)
+ // we would get:
+ // (1, 16, 16, 0)
+ // Instead, we should extract the following map:
+ // (d0, d1, d2, d3) -> (d0, d1, d2)
+ // This way, the corresponding vector/mask type will be:
+ // vector<1x16x16xty>
+ // rather than:
+ // vector<1x16x16x0xty>
+ auto opOperantMapWithoutZeros = opOperandMap.dropZeros();
+ write =
+ state.maskOperation(rewriter, write, linalgOp, opOperantMapWithoutZeros);
// If masked, set in-bounds to true. Masking guarantees that the access will
// be in-bounds.
diff --git a/mlir/lib/IR/AffineMap.cpp b/mlir/lib/IR/AffineMap.cpp
index 62f595299afe2..0d93c3ad19b0f 100644
--- a/mlir/lib/IR/AffineMap.cpp
+++ b/mlir/lib/IR/AffineMap.cpp
@@ -540,6 +540,18 @@ AffineMap AffineMap::dropResults(const llvm::SmallBitVector &positions) const {
return AffineMap::get(getNumDims(), getNumSymbols(), exprs, getContext());
}
+AffineMap AffineMap::dropZeros() {
+ auto exprs = llvm::to_vector<4>(getResults());
+ SmallVector<AffineExpr, 8> newExprs;
+
+ for (auto expr : getResults()) {
+ auto constExpr = dyn_cast<AffineConstantExpr>(expr);
+ if (!constExpr)
+ newExprs.push_back(expr);
+ }
+ return AffineMap::get(getNumDims(), getNumSymbols(), newExprs, getContext());
+}
+
AffineMap AffineMap::compose(AffineMap map) const {
assert(getNumDims() == map.getNumResults() && "Number of results mismatch");
// Prepare `map` by concatenating the symbols and rewriting its exprs.
@@ -579,6 +591,17 @@ SmallVector<int64_t, 4> AffineMap::compose(ArrayRef<int64_t> values) const {
return res;
}
+size_t AffineMap::numOfZeroResults() const {
+ size_t res = 0;
+ for (auto expr : getResults()) {
+ auto constExpr = dyn_cast<AffineConstantExpr>(expr);
+ if (constExpr && constExpr.getValue() == 0)
+ res++;
+ }
+
+ return res;
+}
+
bool AffineMap::isProjectedPermutation(bool allowZeroInResults) const {
if (getNumSymbols() > 0)
return false;
diff --git a/mlir/test/Dialect/Linalg/vectorization-with-patterns.mlir b/mlir/test/Dialect/Linalg/vectorization-with-patterns.mlir
index d7ff1ded9d933..bf015ef409b81 100644
--- a/mlir/test/Dialect/Linalg/vectorization-with-patterns.mlir
+++ b/mlir/test/Dialect/Linalg/vectorization-with-patterns.mlir
@@ -1899,3 +1899,43 @@ module attributes {transform.with_named_sequence} {
// CHECK: %[[VAL_8:.*]] = vector.transpose %[[VAL_7]], [1, 0] : vector<1x4xf32> to vector<4x1xf32>
// CHECK: vector.transfer_write %[[VAL_8]], %{{.*}} {in_bounds = [true, true]} : vector<4x1xf32>, tensor<4x1xf32>
// CHECK: vector.transfer_write %[[VAL_7]], %{{.*}} {in_bounds = [true, true]} : vector<1x4xf32>, tensor<1x4xf32>
+
+// -----
+
+// Extracted from: https://github.com/llvm/llvm-project/issues/97247
+
+#map = affine_map<(d0, d1, d2, d3) -> (d0, d1, d2, d3)>
+#map1 = affine_map<(d0, d1, d2, d3) -> (d0, d1, d2, 0)>
+
+func.func @generic_with_reduction_and_broadcast(%arg0: tensor<1x12x197x197xf32>) -> (tensor<1x12x197x1xf32>) {
+ %0 = tensor.empty() : tensor<1x12x197x1xf32>
+ %1 = linalg.generic {indexing_maps = [#map, #map1], iterator_types = ["parallel", "parallel", "parallel", "reduction"]} ins(%arg0 : tensor<1x12x197x197xf32>) outs(%0 : tensor<1x12x197x1xf32>) {
+ ^bb0(%in: f32, %out: f32):
+ %818 = arith.addf %in, %out : f32
+ linalg.yield %818 : f32
+ } -> tensor<1x12x197x1xf32>
+ return %1 : tensor<1x12x197x1xf32>
+}
+module attributes {transform.with_named_sequence} {
+ transform.named_sequence @__transform_main(%arg0: !transform.any_op {transform.readonly}) {
+ %0 = transform.structured.match ops{["linalg.generic"]} in %arg0 : (!transform.any_op) -> !transform.any_op
+ %1 = transform.get_parent_op %0 {isolated_from_above} : (!transform.any_op) -> !transform.any_op
+ %2 = transform.structured.vectorize_children_and_apply_patterns %1 : (!transform.any_op) -> !transform.any_op
+ transform.yield
+ }
+}
+
+// CHECK: #[[$ATTR_32:.+]] = affine_map<(d0, d1, d2, d3) -> (d0, d1, d2)>
+
+// CHECK-LABEL: func.func @generic_with_reduction_and_broadcast(
+// CHECK-SAME: %[[VAL_0:.*]]: tensor<1x12x197x197xf32>) -> tensor<1x12x197x1xf32> {
+// CHECK: %[[VAL_1:.*]] = arith.constant 0.000000e+00 : f32
+// CHECK: %[[VAL_2:.*]] = arith.constant 0 : index
+// CHECK: %[[VAL_3:.*]] = tensor.empty() : tensor<1x12x197x1xf32>
+// CHECK: %[[VAL_4:.*]] = vector.transfer_read %[[VAL_0]]{{\[}}%[[VAL_2]], %[[VAL_2]], %[[VAL_2]], %[[VAL_2]]], %[[VAL_1]] {in_bounds = [true, true, true, true]} : tensor<1x12x197x197xf32>, vector<1x12x197x197xf32>
+// CHECK: %[[VAL_5:.*]] = vector.transfer_read %[[VAL_3]]{{\[}}%[[VAL_2]], %[[VAL_2]], %[[VAL_2]], %[[VAL_2]]], %[[VAL_1]] {in_bounds = [true, true, true], permutation_map = #[[$ATTR_32]]} : tensor<1x12x197x1xf32>, vector<1x12x197xf32>
+// CHECK: %[[VAL_6:.*]] = vector.multi_reduction <add>, %[[VAL_4]], %[[VAL_5]] [3] : vector<1x12x197x197xf32> to vector<1x12x197xf32>
+// CHECK: %[[VAL_7:.*]] = vector.broadcast %[[VAL_6]] : vector<1x12x197xf32> to vector<1x1x12x197xf32>
+// CHECK: %[[VAL_8:.*]] = vector.transpose %[[VAL_7]], [1, 2, 3, 0] : vector<1x1x12x197xf32> to vector<1x12x197x1xf32>
+// CHECK: %[[VAL_9:.*]] = vector.transfer_write %[[VAL_8]], %[[VAL_3]]{{\[}}%[[VAL_2]], %[[VAL_2]], %[[VAL_2]], %[[VAL_2]]] {in_bounds = [true, true, true, true]} : vector<1x12x197x1xf32>, tensor<1x12x197x1xf32>
+// CHECK: return %[[VAL_9]] : tensor<1x12x197x1xf32>
diff --git a/mlir/test/Dialect/Linalg/vectorization.mlir b/mlir/test/Dialect/Linalg/vectorization.mlir
index bbeccc7fecd68..2464759522c0f 100644
--- a/mlir/test/Dialect/Linalg/vectorization.mlir
+++ b/mlir/test/Dialect/Linalg/vectorization.mlir
@@ -147,6 +147,51 @@ module attributes {transform.with_named_sequence} {
// -----
+#map = affine_map<(d0, d1) -> (d0, d1)>
+#map1 = affine_map<(d0, d1) -> (d0, 0)>
+
+func.func @dynamic_generic_with_reduction_and_broadcast(%arg0: tensor<?x?xf32>, %init: tensor<?x?xf32>) -> (tensor<?x?xf32>) {
+ %0 = linalg.generic { indexing_maps = [#map, #map1],
+ iterator_types = ["parallel", "reduction"]}
+ ins(%arg0 : tensor<?x?xf32>)
+ outs(%init : tensor<?x?xf32>) {
+ ^bb0(%in: f32, %out: f32):
+ %1 = arith.addf %in, %out : f32
+ linalg.yield %1 : f32
+ } -> tensor<?x?xf32>
+ return %0 : tensor<?x?xf32>
+}
+// CHECK: #[[$MAP:.+]] = affine_map<(d0, d1) -> (d0)>
+
+// CHECK-LABEL: func.func @dynamic_generic_with_reduction_and_broadcast(
+// CHECK-SAME: %[[VAL_0:.*]]: tensor<?x?xf32>,
+// CHECK-SAME: %[[VAL_1:.*]]: tensor<?x?xf32>) -> tensor<?x?xf32> {
+// CHECK: %[[VAL_2:.*]] = arith.constant 0 : index
+// CHECK: %[[VAL_3:.*]] = tensor.dim %[[VAL_0]], %[[VAL_2]] : tensor<?x?xf32>
+// CHECK: %[[VAL_4:.*]] = arith.constant 1 : index
+// CHECK: %[[VAL_5:.*]] = tensor.dim %[[VAL_0]], %[[VAL_4]] : tensor<?x?xf32>
+// CHECK: %[[VAL_6:.*]] = arith.constant 0 : index
+// CHECK: %[[VAL_7:.*]] = arith.constant 0.000000e+00 : f32
+// CHECK: %[[VAL_8:.*]] = vector.create_mask %[[VAL_3]], %[[VAL_5]] : vector<4x4xi1>
+// CHECK: %[[VAL_9:.*]] = vector.mask %[[VAL_8]] { vector.transfer_read %[[VAL_0]]{{\[}}%[[VAL_6]], %[[VAL_6]]], %[[VAL_7]] {in_bounds = [true, true]} : tensor<?x?xf32>, vector<4x4xf32> } : vector<4x4xi1> -> vector<4x4xf32>
+// CHECK: %[[VAL_10:.*]] = arith.constant 0.000000e+00 : f32
+// CHECK: %[[VAL_11:.*]] = vector.create_mask %[[VAL_3]] : vector<4xi1>
+// CHECK: %[[VAL_12:.*]] = vector.mask %[[VAL_11]] { vector.transfer_read %[[VAL_1]]{{\[}}%[[VAL_6]], %[[VAL_6]]], %[[VAL_10]] {in_bounds = [true], permutation_map = #[[$MAP]]} : tensor<?x?xf32>, vector<4xf32> } : vector<4xi1> -> vector<4xf32>
+// CHECK: %[[VAL_13:.*]] = vector.mask %[[VAL_8]] { vector.multi_reduction <add>, %[[VAL_9]], %[[VAL_12]] [1] : vector<4x4xf32> to vector<4xf32> } : vector<4x4xi1> -> vector<4xf32>
+// CHECK: %[[VAL_14:.*]] = arith.constant 0 : index
+// CHECK: %[[VAL_15:.*]] = vector.mask %[[VAL_11]] { vector.transfer_write %[[VAL_13]], %[[VAL_1]]{{\[}}%[[VAL_14]], %[[VAL_14]]] {in_bounds = [true], permutation_map = #[[$MAP]]} : vector<4xf32>, tensor<?x?xf32> } : vector<4xi1> -> tensor<?x?xf32>
+// CHECK: return %[[VAL_15]] : tensor<?x?xf32>
+
+module attributes {transform.with_named_sequence} {
+ transform.named_sequence @__transform_main(%arg1: !transform.any_op {transform.readonly}) {
+ %0 = transform.structured.match ops{["linalg.generic"]} in %arg1 : (!transform.any_op) -> !transform.any_op
+ transform.structured.vectorize %0 vector_sizes [4, 4] : !transform.any_op
+ transform.yield
+ }
+}
+
+// -----
+
func.func @vectorize_dynamic_2d_transpose(%arg0: tensor<?x?xf32>,
%arg1: tensor<?x?xf32>,
%arg2: tensor<?x?xf32>) -> tensor<?x?xf32> {
``````````
</details>
https://github.com/llvm/llvm-project/pull/99015
More information about the Mlir-commits
mailing list