Revert "[MLIR][Vector] Generalize DropUnitDimFromElementwiseOps to non leading / trailing dimensions." (#97652)

Reverts llvm/llvm-project#92934 because it breaks some lowering. To
repro: `mlir-opt -test-vector-transfer-flatten-patterns ~/repro.mlir`

```mlir
func.func @unit_dim_folding(%arg0: vector<1x1xf32>) -> vector<1x1xf32> {
  %cst = arith.constant dense<0.000000e+00> : vector<1x1xf32>
  %0 = arith.mulf %arg0, %cst : vector<1x1xf32>
  return %0 : vector<1x1xf32>
}
```
This commit is contained in:
Han-Chung Wang
2024-07-03 16:03:41 -07:00
committed by GitHub
parent af7ee51a90
commit eaabd762bd
2 changed files with 26 additions and 65 deletions

View File

@@ -1622,27 +1622,7 @@ struct ChainedReduction final : OpRewritePattern<vector::ReductionOp> {
}
};
// Scalable unit dimensions are not supported. Folding such dimensions would
// require "shifting" the scalable flag onto some other fixed-width dim (e.g.
// vector<[1]x4xf32> -> vector<[4]xf32>). This could be implemented in the
// future.
static VectorType dropNonScalableUnitDimFromType(VectorType inVecTy) {
auto inVecShape = inVecTy.getShape();
SmallVector<int64_t> newShape;
SmallVector<bool> newScalableDims;
for (auto [dim, isScalable] :
llvm::zip_equal(inVecShape, inVecTy.getScalableDims())) {
if (dim == 1 && !isScalable)
continue;
newShape.push_back(dim);
newScalableDims.push_back(isScalable);
}
return VectorType::get(newShape, inVecTy.getElementType(), newScalableDims);
}
/// For vectors with at least an unit dim, replaces:
/// For vectors with either leading or trailing unit dim, replaces:
/// elementwise(a, b)
/// with:
/// sc_a = shape_cast(a)
@@ -1654,16 +1634,20 @@ static VectorType dropNonScalableUnitDimFromType(VectorType inVecTy) {
/// required to be rank > 1.
///
/// Ex:
/// ```
/// %mul = arith.mulf %B_row, %A_row : vector<1x[4]xf32>
/// %cast = vector.shape_cast %mul : vector<1x[4]xf32> to vector<[4]xf32>
/// ```
///
/// gets converted to:
///
/// ```
/// %B_row_sc = vector.shape_cast %B_row : vector<1x[4]xf32> to vector<[4]xf32>
/// %A_row_sc = vector.shape_cast %A_row : vector<1x[4]xf32> to vector<[4]xf32>
/// %mul = arith.mulf %B_row_sc, %A_row_sc : vector<[4]xf32>
/// %cast_new = vector.shape_cast %mul : vector<[4]xf32> to vector<1x[4]xf32>
/// %cast = vector.shape_cast %cast_new : vector<1x[4]xf32> to vector<[4]xf32>
/// ```
///
/// Patterns for folding shape_casts should instantly eliminate `%cast_new` and
/// `%cast`.
@@ -1683,29 +1667,42 @@ struct DropUnitDimFromElementwiseOps final
// guaranteed to have identical shapes (with some exceptions such as
// `arith.select`) and it suffices to only check one of them.
auto sourceVectorType = dyn_cast<VectorType>(op->getOperand(0).getType());
if (!sourceVectorType || sourceVectorType.getRank() < 2)
if (!sourceVectorType)
return failure();
if (sourceVectorType.getRank() < 2)
return failure();
bool hasTrailingDimUnitFixed =
((sourceVectorType.getShape().back() == 1) &&
(!sourceVectorType.getScalableDims().back()));
bool hasLeadingDimUnitFixed =
((sourceVectorType.getShape().front() == 1) &&
(!sourceVectorType.getScalableDims().front()));
if (!hasLeadingDimUnitFixed && !hasTrailingDimUnitFixed)
return failure();
// Drop leading/trailing unit dim by applying vector.shape_cast to all
// operands
int64_t dim = hasLeadingDimUnitFixed ? 0 : sourceVectorType.getRank() - 1;
SmallVector<Value> newOperands;
auto loc = op->getLoc();
for (auto operand : op->getOperands()) {
auto opVectorType = cast<VectorType>(operand.getType());
auto newVType = dropNonScalableUnitDimFromType(opVectorType);
if (newVType == opVectorType)
return rewriter.notifyMatchFailure(op, "No unit dimension to remove.");
VectorType newVType = VectorType::Builder(opVectorType).dropDim(dim);
auto opSC = rewriter.create<vector::ShapeCastOp>(loc, newVType, operand);
newOperands.push_back(opSC);
}
VectorType newResultVectorType =
dropNonScalableUnitDimFromType(resultVectorType);
// Create an updated elementwise Op without unit dim.
VectorType::Builder(resultVectorType).dropDim(dim);
// Create an updated elementwise Op without leading/trailing unit dim
Operation *elementwiseOp =
rewriter.create(loc, op->getName().getIdentifier(), newOperands,
newResultVectorType, op->getAttrs());
// Restore the unit dim by applying vector.shape_cast to the result.
// Restore the leading/trailing unit dim by applying vector.shape_cast
// to the result
rewriter.replaceOpWithNewOp<ShapeCastOp>(op, resultVectorType,
elementwiseOp->getResult(0));

View File

@@ -604,42 +604,6 @@ func.func @fold_unit_dims_entirely(%arg0 : vector<8xi32>,
// -----
func.func @fold_inner_unit_dim(%arg0 : vector<8x1x3xf128>,
%arg1 : vector<1x8x3xf128>) -> vector<8x3xf128> {
%sc_arg1 = vector.shape_cast %arg1 : vector<1x8x3xf128> to vector<8x1x3xf128>
%mul = arith.mulf %arg0, %sc_arg1 : vector<8x1x3xf128>
%res = vector.shape_cast %mul : vector<8x1x3xf128> to vector<8x3xf128>
return %res : vector<8x3xf128>
}
// CHECK-LABEL: func.func @fold_inner_unit_dim(
// CHECK-SAME: %[[VAL_0:.*]]: vector<8x1x3xf128>,
// CHECK-SAME: %[[VAL_1:.*]]: vector<1x8x3xf128>) -> vector<8x3xf128> {
// CHECK: %[[VAL_2:.*]] = vector.shape_cast %[[VAL_0]] : vector<8x1x3xf128> to vector<8x3xf128>
// CHECK: %[[VAL_3:.*]] = vector.shape_cast %[[VAL_1]] : vector<1x8x3xf128> to vector<8x3xf128>
// CHECK: %[[VAL_4:.*]] = arith.mulf %[[VAL_2]], %[[VAL_3]] : vector<8x3xf128>
// CHECK: return %[[VAL_4]] : vector<8x3xf128>
// -----
func.func @fold_inner_unit_dim_scalable(%arg0 : vector<8x1x[1]x3xf128>,
%arg1 : vector<1x8x[1]x3xf128>) -> vector<8x[1]x3xf128> {
%sc_arg1 = vector.shape_cast %arg1 : vector<1x8x[1]x3xf128> to vector<8x1x[1]x3xf128>
%mul = arith.mulf %arg0, %sc_arg1 : vector<8x1x[1]x3xf128>
%res = vector.shape_cast %mul : vector<8x1x[1]x3xf128> to vector<8x[1]x3xf128>
return %res : vector<8x[1]x3xf128>
}
// CHECK-LABEL: func.func @fold_inner_unit_dim_scalable(
// CHECK-SAME: %[[VAL_0:.*]]: vector<8x1x[1]x3xf128>,
// CHECK-SAME: %[[VAL_1:.*]]: vector<1x8x[1]x3xf128>) -> vector<8x[1]x3xf128> {
// CHECK: %[[VAL_2:.*]] = vector.shape_cast %[[VAL_0]] : vector<8x1x[1]x3xf128> to vector<8x[1]x3xf128>
// CHECK: %[[VAL_3:.*]] = vector.shape_cast %[[VAL_1]] : vector<1x8x[1]x3xf128> to vector<8x[1]x3xf128>
// CHECK: %[[VAL_4:.*]] = arith.mulf %[[VAL_2]], %[[VAL_3]] : vector<8x[1]x3xf128>
// CHECK: return %[[VAL_4]] : vector<8x[1]x3xf128>
// -----
func.func @negative_out_of_bound_transfer_read(
%arg : memref<?x4x3x2xi8, strided<[24, 6, 2, 1], offset: ?>>) -> vector<5x4x3x2xi8> {
%c0 = arith.constant 0 : index