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OptimizeInstruction: Optimize any boolean & (No overlap with boolean's LSB) ==> 0 #7505

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b67c4ac
opt for #7481
xuruiyang2002 Apr 16, 2025
340fd1b
tests
xuruiyang2002 Apr 16, 2025
6aab029
refactor to be generalized
xuruiyang2002 Apr 19, 2025
11992ac
update test due to refactoring
xuruiyang2002 Apr 19, 2025
bfdc24c
No need for special-cased 0
xuruiyang2002 Apr 24, 2025
27ac17f
Avoid redundant replaceCurrent
xuruiyang2002 Apr 24, 2025
2f2dbfb
And is commutative
xuruiyang2002 Apr 24, 2025
a8216a0
Update test
xuruiyang2002 Apr 24, 2025
2bbd847
Update test
xuruiyang2002 Apr 24, 2025
dad3fd5
Update test
xuruiyang2002 Apr 24, 2025
51196f8
Deal with cornor case
xuruiyang2002 Apr 24, 2025
131a423
Add cornor case
xuruiyang2002 Apr 24, 2025
0f09450
Refactor
xuruiyang2002 Apr 24, 2025
37653fe
Update src/passes/OptimizeInstructions.cpp
xuruiyang2002 Apr 29, 2025
0d8c6ad
Avoid redundant code
xuruiyang2002 May 1, 2025
f6de81a
Update test
xuruiyang2002 May 1, 2025
3f900fe
Adjust comments
xuruiyang2002 May 1, 2025
4dfe6ee
Adjust comments
xuruiyang2002 May 1, 2025
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41 changes: 41 additions & 0 deletions src/passes/OptimizeInstructions.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -837,6 +837,9 @@ struct OptimizeInstructions
if (auto* ret = combineAnd(curr)) {
return replaceCurrent(ret);
}
if (auto* ret = optimizeAndNoOverlappingBits(curr)) {
return replaceCurrent(ret);
}
}
// for or, we can potentially combine
if (curr->op == OrInt32) {
Expand All @@ -850,6 +853,12 @@ struct OptimizeInstructions
return replaceCurrent(ret);
}
}
if (curr->op == AndInt64) {
if (auto* ret = optimizeAndNoOverlappingBits(curr)) {
return replaceCurrent(ret);
}
}

// relation/comparisons allow for math optimizations
if (curr->isRelational()) {
if (auto* ret = optimizeRelational(curr)) {
Expand Down Expand Up @@ -3549,6 +3558,38 @@ struct OptimizeInstructions
return nullptr;
}

// Bitwise AND of a value with bits in [0, n) and a constant with no bits in
// [0, n) always yields 0. Replace with zero.
Expression* optimizeAndNoOverlappingBits(Binary* curr) {
assert(curr->op == AndInt32 || curr->op == AndInt64);

using namespace Abstract;
using namespace Match;

auto* left = curr->left;
auto* right = curr->right;

// Check left's max bits and right is constant.
auto leftMaxBits = Bits::getMaxBits(left, this);
uint64_t maskLeft;
if (leftMaxBits == 64) {
// If we know nothing useful about the bits on the left,
// we can not optimize.
return nullptr;
} else {
maskLeft = (1ULL << leftMaxBits) - 1;
}
if (auto* c = right->dynCast<Const>()) {
uint64_t constantValue = c->value.getInteger();
if ((constantValue & maskLeft) == 0) {
return getDroppedChildrenAndAppend(
curr, LiteralUtils::makeZero(left->type, *getModule()));
}
}

return nullptr;
}

// We can combine `or` operations, e.g.
// (x > y) | (x == y) ==> x >= y
// (x != 0) | (y != 0) ==> (x | y) != 0
Expand Down
186 changes: 177 additions & 9 deletions test/lit/passes/optimize-instructions-mvp.wast
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Original file line number Diff line number Diff line change
Expand Up @@ -1442,9 +1442,12 @@
)
;; CHECK: (func $canonicalize-consts-vars (param $x i32) (param $y i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.and
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: (i32.const 2)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
Expand Down Expand Up @@ -1482,6 +1485,7 @@
;; CHECK-NEXT: )
(func $canonicalize-consts-vars (param $x i32) (param $y i32)
(drop (i32.and (i32.const 1) (i32.const 2)))
(drop (i32.and (i32.const 2) (i32.const 1)))
(drop (i32.and (local.get $x) (i32.const 3)))
(drop (i32.and (i32.const 4) (local.get $x)))
(drop (i32.and (local.get $x) (local.get $y)))
Expand Down Expand Up @@ -2865,18 +2869,18 @@
(i32.const 24)
)
)
;; CHECK: (func $sext-24-and-127-128 (result i32)
;; CHECK: (func $sext-24-and-127-unknown (param $x i32) (result i32)
;; CHECK-NEXT: (i32.and
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 127)
;; CHECK-NEXT: (i32.const 128)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $sext-24-and-127-128 (result i32)
(func $sext-24-and-127-unknown (param $x i32) (result i32)
(i32.shr_s
(i32.shl
(i32.and ;; takes the min, here it is ok
(i32.const 127)
(i32.const 128)
(local.get $x)
)
(i32.const 24)
)
Expand Down Expand Up @@ -6972,7 +6976,7 @@
)
)
)
;; CHECK: (func $de-morgan-2 (param $x i32) (param $y i32)
;; CHECK: (func $de-morgan-2 (param $x i32) (param $y i32) (param $z i64)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.eqz
;; CHECK-NEXT: (i32.or
Expand Down Expand Up @@ -7022,7 +7026,9 @@
;; CHECK-NEXT: (i32.eqz
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 2)
;; CHECK-NEXT: (i32.wrap_i64
;; CHECK-NEXT: (local.get $z)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
Expand All @@ -7031,7 +7037,7 @@
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $de-morgan-2 (param $x i32) (param $y i32)
(func $de-morgan-2 (param $x i32) (param $y i32) (param $z i64)
(drop
(i32.and (i32.eqz (local.get $x)) (i32.eqz (local.get $y)))
)
Expand All @@ -7048,7 +7054,7 @@
(i32.and (local.get $x) (i32.eqz (local.get $y)))
)
(drop
(i32.and (i32.eqz (local.get $x)) (i32.wrap_i64 (i64.const 2)))
(i32.and (i32.eqz (local.get $x)) (i32.wrap_i64 (local.get $z)))
)
(drop
(i32.and (i32.wrap_i64 (i64.const 1)) (i32.eqz (local.get $y)))
Expand Down Expand Up @@ -17773,4 +17779,166 @@
(i32.const 1)
)
)
;; CHECK: (func $no-overlapping-bits-corner-case (param $x i32) (param $y i64)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i64.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i64.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.and
;; CHECK-NEXT: (i32.const -2147483648)
;; CHECK-NEXT: (i32.const 2147483647)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i64.and
;; CHECK-NEXT: (i64.const 2)
;; CHECK-NEXT: (i64.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i64.and
;; CHECK-NEXT: (i64.const 2147483648)
;; CHECK-NEXT: (i64.const 2147483647)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i64.and
;; CHECK-NEXT: (i64.const -9223372036854775808)
;; CHECK-NEXT: (i64.const 9223372036854775807)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i64.and
;; CHECK-NEXT: (local.get $y)
;; CHECK-NEXT: (i64.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.and
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i64.and
;; CHECK-NEXT: (local.get $y)
;; CHECK-NEXT: (i64.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.and
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.and
;; CHECK-NEXT: (i32.const 2147483647)
;; CHECK-NEXT: (i32.const -2147483647)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i64.and
;; CHECK-NEXT: (i64.const 2147483647)
;; CHECK-NEXT: (i64.const 2147483649)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $no-overlapping-bits-corner-case (param $x i32) (param $y i64)
;; optimizeAndNoOverlappingBits simplifies AND operations where
;; - the left value covers bits in [0, n)
;; - the right operand is a constant with no bits in [0, n)
;; Result is simplified to zero.

;; No any bit overlapped, optimized.
(drop
(i64.and
(i64.const 1)
(i64.const 2)
)
)
(drop
(i32.and
(i32.const 0)
(local.get $x)
)
)
(drop
(i64.and
(i64.const 0)
(local.get $y)
)
)
;; optimizeAndNoOverlappingBits focuses on the case where one side is constant,
;; both-constant cases are handled by Precompute, so they are skipped here.
(drop
(i32.and
(i32.const 0x80000000)
(i32.const 0x7fffffff)
)
)
(drop
(i64.and
(i64.const 2)
(i64.const 1)
)
)
(drop
(i64.and
(i64.const 0x80000000)
(i64.const 0x7fffffff)
)
)
;; Know nothing useful about the bits on the left, so we can not optimize.
(drop
(i64.and
(i64.const 0x8000000000000000)
(i64.const 0x7fffffffffffffff)
)
)
(drop
(i64.and
(local.get $y)
(i64.const 1)
)
)
;; Know nothing useful about the value of the right, so we can not optimize.
(drop
(i32.and
(i32.const 1)
(local.get $x)
)
)
(drop
(i64.and
(i64.const 1)
(local.get $y)
)
)
;; One bit overlapped, so we can not optimized.
(drop
(i32.and
(local.get $x)
(i32.const 1)
)
)
(drop
(i32.and
(i32.const 0x7fffffff)
(i32.const 0x80000001)
)
)
(drop
(i64.and
(i64.const 0x7fffffff)
(i64.const 0x80000001)
)
)
)
)
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