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[mlir][scf] Fix loop iteration calculation for negative step in LoopPipelining #110035

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Merged
merged 1 commit into from
Sep 25, 2024
Merged

[mlir][scf] Fix loop iteration calculation for negative step in LoopPipelining #110035

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23 changes: 15 additions & 8 deletions mlir/lib/Dialect/SCF/Transforms/LoopPipelining.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -648,15 +648,22 @@ LoopPipelinerInternal::emitEpilogue(RewriterBase &rewriter,
// bounds_range = ub - lb
// total_iterations = (bounds_range + step - 1) / step
Type t = lb.getType();
Value minus1 =
rewriter.create<arith::ConstantOp>(loc, rewriter.getIntegerAttr(t, -1));
Value boundsRange = rewriter.create<arith::SubIOp>(loc, ub, lb);
Value rangeIncr = rewriter.create<arith::AddIOp>(loc, boundsRange, step);
Value rangeDecr = rewriter.create<arith::AddIOp>(loc, rangeIncr, minus1);
Value totalIterations = rewriter.create<arith::DivUIOp>(loc, rangeDecr, step);

Value zero =
rewriter.create<arith::ConstantOp>(loc, rewriter.getIntegerAttr(t, 0));
Value one =
rewriter.create<arith::ConstantOp>(loc, rewriter.getIntegerAttr(t, 1));
Value minusOne =
rewriter.create<arith::ConstantOp>(loc, rewriter.getIntegerAttr(t, -1));
Value stepLessZero = rewriter.create<arith::CmpIOp>(
loc, arith::CmpIPredicate::slt, step, zero);
Value stepDecr =
rewriter.create<arith::SelectOp>(loc, stepLessZero, one, minusOne);

Value rangeDiff = rewriter.create<arith::SubIOp>(loc, ub, lb);
Value rangeIncrStep = rewriter.create<arith::AddIOp>(loc, rangeDiff, step);
Value rangeDecr =
rewriter.create<arith::AddIOp>(loc, rangeIncrStep, stepDecr);
Value totalIterations = rewriter.create<arith::DivSIOp>(loc, rangeDecr, step);

SmallVector<Value> predicates(maxStage + 1);
for (int64_t i = 0; i < maxStage; i++) {
Expand All @@ -665,7 +672,7 @@ LoopPipelinerInternal::emitEpilogue(RewriterBase &rewriter,
Value minusI =
rewriter.create<arith::ConstantOp>(loc, rewriter.getIntegerAttr(t, -i));
Value iterI = rewriter.create<arith::AddIOp>(
loc, rewriter.create<arith::AddIOp>(loc, totalIterations, minus1),
loc, rewriter.create<arith::AddIOp>(loc, totalIterations, minusOne),
minusI);
// newLastIter = lb + step * iterI
Value newlastIter = rewriter.create<arith::AddIOp>(
Expand Down
47 changes: 29 additions & 18 deletions mlir/test/Dialect/SCF/loop-pipelining.mlir
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Original file line number Diff line number Diff line change
Expand Up @@ -766,24 +766,29 @@ func.func @stage_0_value_escape(%A: memref<?xf32>, %result: memref<?xf32>, %ub:

// Check for predicated epilogue for dynamic loop.
// CHECK-LABEL: dynamic_loop(
// CHECK: %[[C0:.*]] = arith.constant 0 : index
// CHECK: %{{.*}}:2 = scf.for %[[ARG5:.*]] = %{{.*}} to %{{.*}} step %{{.*}} iter_args(%[[ARG6:.*]] = %{{.*}}, %[[ARG7:.*]] = %{{.*}})
// CHECK-DAG: %[[C1:.*]] = arith.constant 1 : index
// CHECK-DAG: %[[C0:.*]] = arith.constant 0 : index
// CHECK-DAG: %[[CM1:.*]] = arith.constant -1 : index
// CHECK: %[[UBM:.*]] = arith.subi %[[UB:.*]], %{{.*}}
// CHECK: %{{.*}}:2 = scf.for %[[ARG5:.*]] = %[[LB:.*]] to %[[UBM]] step %[[STEP:.*]] iter_args(%[[ARG6:.*]] = %{{.*}}, %[[ARG7:.*]] = %{{.*}})
// CHECK: memref.store %[[ARG6]], %{{.*}}[%[[ARG5]]]
// CHECK: %[[ADDF_24:.*]] = arith.addf %[[ARG7]], %{{.*}}
// CHECK: %[[MULI_25:.*]] = arith.muli %{{.*}}, %{{.*}}
// CHECK: %[[ADDI_26:.*]] = arith.addi %[[ARG5]], %[[MULI_25]]
// CHECK: %[[LOAD_27:.*]] = memref.load %{{.*}}[%[[ADDI_26]]]
// CHECK: scf.yield %[[ADDF_24]], %[[LOAD_27]]
// CHECK: }
// CHECK: %[[SUBI_10:.*]] = arith.subi %{{.*}}, %{{.*}}
// CHECK: %[[ADDI_11:.*]] = arith.addi %[[SUBI_10]], %{{.*}}
// CHECK: %[[ADDI_12:.*]] = arith.addi %[[ADDI_11]], %{{.*}}-1
// CHECK: %[[DIVUI_13:.*]] = arith.divui %[[ADDI_12]], %{{.*}}
// CHECK: %[[ADDI_14:.*]] = arith.addi %[[DIVUI_13]], %{{.*}}-1
// CHECK: %[[CMPI_10:.*]] = arith.cmpi slt, %[[STEP]], %[[C0]]
// CHECK: %[[SEL_10:.*]] = arith.select %[[CMPI_10]], %[[C1]], %[[CM1]]
// CHECK: %[[SUBI_10:.*]] = arith.subi %[[UB]], %[[LB]]
// CHECK: %[[ADDI_11:.*]] = arith.addi %[[SUBI_10]], %[[STEP]]
// CHECK: %[[ADDI_12:.*]] = arith.addi %[[ADDI_11]], %[[SEL_10]]
// CHECK: %[[DIVSI_13:.*]] = arith.divsi %[[ADDI_12]], %[[STEP]]
// CHECK: %[[ADDI_14:.*]] = arith.addi %[[DIVSI_13]], %[[CM1]]
// CHECK: %[[MULI_15:.*]] = arith.muli %{{.*}}, %[[ADDI_14]]
// CHECK: %[[ADDI_16:.*]] = arith.addi %{{.*}}, %[[MULI_15]]
// CHECK: %[[CMPI_17:.*]] = arith.cmpi sge, %[[ADDI_14]], %[[C0]]
// CHECK: %[[ADDI_18:.*]] = arith.addi %[[DIVUI_13]], %{{.*}}-1
// CHECK: %[[ADDI_18:.*]] = arith.addi %[[DIVSI_13]], %{{.*}}-1
// CHECK: %[[ADDI_19:.*]] = arith.addi %[[ADDI_18]], %{{.*}}-1
// CHECK: %[[MULI_20:.*]] = arith.muli %{{.*}}, %[[ADDI_19]]
// CHECK: %[[ADDI_21:.*]] = arith.addi %{{.*}}, %[[MULI_20]]
Expand Down Expand Up @@ -834,32 +839,38 @@ func.func @dynamic_loop(%A: memref<?xf32>, %result: memref<?xf32>, %lb: index, %

// Check for predicated epilogue for dynamic loop.
// CHECK-LABEL: func.func @dynamic_loop_result
// CHECK: %{{.*}}:2 = scf.for %[[ARG5:.*]] = %{{.*}} to %{{.*}} step %{{.*}} iter_args(%[[ARG6:.*]] = %{{.*}}, %[[ARG7:.*]] = %{{.*}})
// CHECK-DAG: %[[C1:.*]] = arith.constant 1 : index
// CHECK-DAG: %[[C0:.*]] = arith.constant 0 : index
// CHECK-DAG: %[[CM1:.*]] = arith.constant -1 : index
// CHECK: %[[UBM:.*]] = arith.subi %[[UB:.*]], %{{.*}}
// CHECK: %{{.*}}:2 = scf.for %[[ARG5:.*]] = %[[LB:.*]] to %[[UBM]] step %[[STEP:.*]] iter_args(%[[ARG6:.*]] = %{{.*}}, %[[ARG7:.*]] = %{{.*}})
// CHECK: %[[ADDF_13:.*]] = arith.addf %[[ARG7]], %[[ARG6]]
// CHECK: %[[MULF_14:.*]] = arith.mulf %[[ADDF_13]], %{{.*}}
// CHECK: %[[ADDI_15:.*]] = arith.addi %[[ARG5]], %{{.*}}
// CHECK: %[[LOAD_16:.*]] = memref.load %{{.*}}[%[[ADDI_15]]]
// CHECK: scf.yield %[[MULF_14]], %[[LOAD_16]]
// CHECK: }
// CHECK: %[[SUBI_4:.*]] = arith.subi %{{.*}}, %{{.*}}
// CHECK: %[[ADDI_5:.*]] = arith.addi %[[SUBI_4]], %{{.*}}
// CHECK: %[[ADDI_6:.*]] = arith.addi %[[ADDI_5]], %{{.*}}-1
// CHECK: %[[DIVUI_7:.*]] = arith.divui %[[ADDI_6]], %{{.*}}
// CHECK: %[[ADDI_8:.*]] = arith.addi %[[DIVUI_7]], %{{.*}}-1
// CHECK: %[[CMPI_9:.*]] = arith.cmpi sge, %[[ADDI_8]], %{{.*}}
// CHECK: %[[IF_10:.*]] = scf.if %[[CMPI_9]]
// CHECK: %[[CMPI_4:.*]] = arith.cmpi slt, %[[STEP]], %[[C0]]
// CHECK: %[[SELECT_5:.*]] = arith.select %[[CMPI_4]], %[[C1]], %[[CM1]]
// CHECK: %[[SUBI_6:.*]] = arith.subi %[[UB]], %[[LB]]
// CHECK: %[[ADDI_7:.*]] = arith.addi %[[SUBI_6]], %[[STEP]]
// CHECK: %[[ADDI_8:.*]] = arith.addi %[[ADDI_7]], %[[SELECT_5]]
// CHECK: %[[DIVSI_9:.*]] = arith.divsi %[[ADDI_8]], %[[STEP]]
// CHECK: %[[ADDI_10:.*]] = arith.addi %[[DIVSI_9]], %[[CM1]]
// CHECK: %[[CMPI_11:.*]] = arith.cmpi sge, %[[ADDI_10]], %[[C0]]
// CHECK: %[[IF_10:.*]] = scf.if %[[CMPI_11]]
// CHECK: %[[ADDF_13:.*]] = arith.addf %{{.*}}#1, %{{.*}}#0
// CHECK: scf.yield %[[ADDF_13]]
// CHECK: } else {
// CHECK: scf.yield %{{.*}}
// CHECK: }
// CHECK: %[[IF_11:.*]] = scf.if %[[CMPI_9]]
// CHECK: %[[IF_11:.*]] = scf.if %[[CMPI_11]]
// CHECK: %[[MULF_13:.*]] = arith.mulf %[[IF_10]], %{{.*}}
// CHECK: scf.yield %[[MULF_13]]
// CHECK: } else {
// CHECK: scf.yield %{{.*}}
// CHECK: }
// CHECK: %[[SELECT_12:.*]] = arith.select %[[CMPI_9]], %[[IF_11]], %{{.*}}#0
// CHECK: %[[SELECT_12:.*]] = arith.select %[[CMPI_11]], %[[IF_11]], %{{.*}}#0
// CHECK: memref.store %[[SELECT_12]], %{{.*}}[%{{.*}}]
func.func @dynamic_loop_result(%A: memref<?xf32>, %result: memref<?xf32>, %lb: index, %ub: index, %step: index) {
%cf0 = arith.constant 1.0 : f32
Expand Down
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