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[mlir][arith] fix ceildivsi lowering #106696

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[mlir][arith] fix ceildivsi lowering #106696

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8 changes: 3 additions & 5 deletions mlir/lib/Dialect/Arith/Transforms/ExpandOps.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,7 @@ struct CeilDivUIOpConverter : public OpRewritePattern<arith::CeilDivUIOp> {

/// Expands CeilDivSIOp (n, m) into
/// 1) x = (m > 0) ? -1 : 1
/// 2) (n*m>0) ? ((n+x) / m) + 1 : - (-n / m)
/// 2) (n*m>0) ? ((n+x) / m) + 1 : n / m
struct CeilDivSIOpConverter : public OpRewritePattern<arith::CeilDivSIOp> {
using OpRewritePattern::OpRewritePattern;
LogicalResult matchAndRewrite(arith::CeilDivSIOp op,
Expand All @@ -80,10 +80,8 @@ struct CeilDivSIOpConverter : public OpRewritePattern<arith::CeilDivSIOp> {
Value xPlusA = rewriter.create<arith::AddIOp>(loc, x, a);
Value xPlusADivB = rewriter.create<arith::DivSIOp>(loc, xPlusA, b);
Value posRes = rewriter.create<arith::AddIOp>(loc, plusOne, xPlusADivB);
// Compute negative res: - ((-a)/b).
Value minusA = rewriter.create<arith::SubIOp>(loc, zero, a);
Value minusADivB = rewriter.create<arith::DivSIOp>(loc, minusA, b);
Value negRes = rewriter.create<arith::SubIOp>(loc, zero, minusADivB);
// Compute negative res: a/b.
Value negRes = rewriter.create<arith::DivSIOp>(loc, a, b);
// Result is (a*b>0) ? pos result : neg result.
// Note, we want to avoid using a*b because of possible overflow.
// The case that matters are a>0, a==0, a<0, b>0 and b<0. We do
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12 changes: 4 additions & 8 deletions mlir/test/Dialect/Arith/expand-ops.mlir
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Original file line number Diff line number Diff line change
Expand Up @@ -15,17 +15,15 @@ func.func @ceildivi(%arg0: i32, %arg1: i32) -> (i32) {
// CHECK: [[TRUE1:%.+]] = arith.addi [[X]], [[ARG0]] : i32
// CHECK: [[TRUE2:%.+]] = arith.divsi [[TRUE1]], [[ARG1]] : i32
// CHECK: [[TRUE3:%.+]] = arith.addi [[ONE]], [[TRUE2]] : i32
// CHECK: [[FALSE1:%.+]] = arith.subi [[ZERO]], [[ARG0]] : i32
// CHECK: [[FALSE2:%.+]] = arith.divsi [[FALSE1]], [[ARG1]] : i32
// CHECK: [[FALSE3:%.+]] = arith.subi [[ZERO]], [[FALSE2]] : i32
// CHECK: [[FALSE:%.+]] = arith.divsi [[ARG0]], [[ARG1]] : i32
// CHECK: [[NNEG:%.+]] = arith.cmpi slt, [[ARG0]], [[ZERO]] : i32
// CHECK: [[NPOS:%.+]] = arith.cmpi sgt, [[ARG0]], [[ZERO]] : i32
// CHECK: [[MNEG:%.+]] = arith.cmpi slt, [[ARG1]], [[ZERO]] : i32
// CHECK: [[MPOS:%.+]] = arith.cmpi sgt, [[ARG1]], [[ZERO]] : i32
// CHECK: [[TERM1:%.+]] = arith.andi [[NNEG]], [[MNEG]] : i1
// CHECK: [[TERM2:%.+]] = arith.andi [[NPOS]], [[MPOS]] : i1
// CHECK: [[CMP2:%.+]] = arith.ori [[TERM1]], [[TERM2]] : i1
// CHECK: [[RES:%.+]] = arith.select [[CMP2]], [[TRUE3]], [[FALSE3]] : i32
// CHECK: [[RES:%.+]] = arith.select [[CMP2]], [[TRUE3]], [[FALSE]] : i32
}

// -----
Expand All @@ -45,17 +43,15 @@ func.func @ceildivi_index(%arg0: index, %arg1: index) -> (index) {
// CHECK: [[TRUE1:%.+]] = arith.addi [[X]], [[ARG0]] : index
// CHECK: [[TRUE2:%.+]] = arith.divsi [[TRUE1]], [[ARG1]] : index
// CHECK: [[TRUE3:%.+]] = arith.addi [[ONE]], [[TRUE2]] : index
// CHECK: [[FALSE1:%.+]] = arith.subi [[ZERO]], [[ARG0]] : index
// CHECK: [[FALSE2:%.+]] = arith.divsi [[FALSE1]], [[ARG1]] : index
// CHECK: [[FALSE3:%.+]] = arith.subi [[ZERO]], [[FALSE2]] : index
// CHECK: [[FALSE:%.+]] = arith.divsi [[ARG0]], [[ARG1]] : index
// CHECK: [[NNEG:%.+]] = arith.cmpi slt, [[ARG0]], [[ZERO]] : index
// CHECK: [[NPOS:%.+]] = arith.cmpi sgt, [[ARG0]], [[ZERO]] : index
// CHECK: [[MNEG:%.+]] = arith.cmpi slt, [[ARG1]], [[ZERO]] : index
// CHECK: [[MPOS:%.+]] = arith.cmpi sgt, [[ARG1]], [[ZERO]] : index
// CHECK: [[TERM1:%.+]] = arith.andi [[NNEG]], [[MNEG]] : i1
// CHECK: [[TERM2:%.+]] = arith.andi [[NPOS]], [[MPOS]] : i1
// CHECK: [[CMP2:%.+]] = arith.ori [[TERM1]], [[TERM2]] : i1
// CHECK: [[RES:%.+]] = arith.select [[CMP2]], [[TRUE3]], [[FALSE3]] : index
// CHECK: [[RES:%.+]] = arith.select [[CMP2]], [[TRUE3]], [[FALSE]] : index
}

// -----
Expand Down