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[mlir][arith] Fix multiplication canonicalizations #144787

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[mlir][arith] Fix multiplication canonicalizations #144787

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14 changes: 11 additions & 3 deletions mlir/lib/Dialect/Arith/IR/ArithCanonicalization.td
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Original file line number Diff line number Diff line change
Expand Up @@ -273,7 +273,7 @@ def RedundantSelectFalse :
Pat<(SelectOp $pred, $a, (SelectOp $pred, $b, $c)),
(SelectOp $pred, $a, $c)>;

// select(pred, false, true) => not(pred)
// select(pred, false, true) => not(pred)
def SelectI1ToNot :
Pat<(SelectOp $pred,
(ConstantLikeMatcher ConstantAttr<I1Attr, "0">),
Expand Down Expand Up @@ -376,6 +376,12 @@ def TruncationMatchesShiftAmount :
CPred<"(getScalarOrElementWidth($0) - getScalarOrElementWidth($1)) == "
"*getIntOrSplatIntValue($2)">]>>;

def ValueWidthMatchesShiftAmount :
Constraint<And<[
CPred<"succeeded(getIntOrSplatIntValue($1))">,
CPred<"getScalarOrElementWidth($0) == "
"*getIntOrSplatIntValue($1)">]>>;

// trunci(extsi(x)) -> extsi(x), when only the sign-extension bits are truncated
def TruncIExtSIToExtSI :
Pat<(Arith_TruncIOp:$tr (Arith_ExtSIOp:$ext $x)),
Expand Down Expand Up @@ -406,7 +412,8 @@ def TruncIShrUIMulIToMulSIExtended :
(Arith_MulSIExtendedOp:$res__1 $x, $y),
[(ValuesWithSameType $tr, $x, $y),
(ValueWiderThan $mul, $x),
(TruncationMatchesShiftAmount $mul, $x, $c0)]>;
(TruncationMatchesShiftAmount $mul, $x, $c0),
(ValueWidthMatchesShiftAmount $x, $c0)]>;

// trunci(shrui(mul(zext(x), zext(y)), c)) -> mului_extended(x, y)
def TruncIShrUIMulIToMulUIExtended :
Expand All @@ -417,7 +424,8 @@ def TruncIShrUIMulIToMulUIExtended :
(Arith_MulUIExtendedOp:$res__1 $x, $y),
[(ValuesWithSameType $tr, $x, $y),
(ValueWiderThan $mul, $x),
(TruncationMatchesShiftAmount $mul, $x, $c0)]>;
(TruncationMatchesShiftAmount $mul, $x, $c0),
(ValueWidthMatchesShiftAmount $x, $c0)]>;

//===----------------------------------------------------------------------===//
// TruncIOp
Expand Down
32 changes: 31 additions & 1 deletion mlir/test/Dialect/Arith/canonicalize.mlir
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Original file line number Diff line number Diff line change
Expand Up @@ -1000,7 +1000,7 @@ func.func @tripleAddAddOvf2(%arg0: index) -> index {


// CHECK-LABEL: @foldSubXX_tensor
// CHECK: %[[c0:.+]] = arith.constant dense<0> : tensor<10xi32>
// CHECK: %[[c0:.+]] = arith.constant dense<0> : tensor<10xi32>
// CHECK: %[[sub:.+]] = arith.subi
// CHECK: return %[[c0]], %[[sub]]
func.func @foldSubXX_tensor(%static : tensor<10xi32>, %dyn : tensor<?x?xi32>) -> (tensor<10xi32>, tensor<?x?xi32>) {
Expand Down Expand Up @@ -2966,6 +2966,21 @@ func.func @wideMulToMulSIExtended(%a: i32, %b: i32) -> i32 {
return %hi : i32
}

// Verify that the signed extended multiplication pattern does not match
// if the right shift does not match the bitwidth of the multipliers.

// CHECK-LABEL: @wideMulToMulSIExtendedWithWrongShift
// CHECK-NOT: arith.mulsi_extended
func.func @wideMulToMulSIExtendedWithWrongShift(%a: i32, %b: i32) -> i32 {
%x = arith.extsi %a: i32 to i33
%y = arith.extsi %b: i32 to i33
%m = arith.muli %x, %y: i33
%c1 = arith.constant 1: i33
%sh = arith.shrui %m, %c1 : i33
%hi = arith.trunci %sh: i33 to i32
return %hi : i32
}

// CHECK-LABEL: @wideMulToMulSIExtendedVector
// CHECK-SAME: (%[[A:.+]]: vector<3xi32>, %[[B:.+]]: vector<3xi32>)
// CHECK-NEXT: %[[LOW:.+]], %[[HIGH:.+]] = arith.mulsi_extended %[[A]], %[[B]] : vector<3xi32>
Expand Down Expand Up @@ -2994,6 +3009,21 @@ func.func @wideMulToMulUIExtended(%a: i32, %b: i32) -> i32 {
return %hi : i32
}

// Verify that the unsigned extended multiplication pattern does not match
// if the right shift does not match the bitwidth of the multipliers.

// CHECK-LABEL: @wideMulToMulUIExtendedWithWrongShift
// CHECK-NOT: arith.mului_extended
func.func @wideMulToMulUIExtendedWithWrongShift(%a: i32, %b: i32) -> i32 {
%x = arith.extui %a: i32 to i33
%y = arith.extui %b: i32 to i33
%m = arith.muli %x, %y: i33
%c1 = arith.constant 1: i33
%sh = arith.shrui %m, %c1 : i33
%hi = arith.trunci %sh: i33 to i32
return %hi : i32
}

// CHECK-LABEL: @wideMulToMulUIExtendedVector
// CHECK-SAME: (%[[A:.+]]: vector<3xi32>, %[[B:.+]]: vector<3xi32>)
// CHECK-NEXT: %[[LOW:.+]], %[[HIGH:.+]] = arith.mului_extended %[[A]], %[[B]] : vector<3xi32>
Expand Down
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