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Use fallthrough in optimizeInstructions to further optimize (unsigned)x < 0 ==> i32(0) #7480

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Merged
merged 11 commits into from
Apr 24, 2025
Merged

Use fallthrough in optimizeInstructions to further optimize (unsigned)x < 0 ==> i32(0) #7480

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292d23d
opt for #7455
xuruiyang2002 Apr 10, 2025
1723a46
generalize existing rule
xuruiyang2002 Apr 11, 2025
112e40d
tests
xuruiyang2002 Apr 11, 2025
8910adb
NFC
xuruiyang2002 Apr 11, 2025
0e19573
Fix: use makeConst instead of makeFromInt32
xuruiyang2002 Apr 12, 2025
5ba769e
Fix: apply getFallthrough at lt_u rule
xuruiyang2002 Apr 16, 2025
b2d953f
Remove original fix
xuruiyang2002 Apr 16, 2025
ffe6200
Update test
xuruiyang2002 Apr 16, 2025
45e6ef6
Add test for i64
xuruiyang2002 Apr 16, 2025
9eb6ec5
fix: reuse const c
xuruiyang2002 Apr 19, 2025
1f06dbc
update test
xuruiyang2002 Apr 19, 2025
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10 changes: 6 additions & 4 deletions src/passes/OptimizeInstructions.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -570,11 +570,13 @@ struct OptimizeInstructions
return replaceCurrent(getDroppedChildrenAndAppend(curr, c));
}
// unsigned(x) < 0 => i32(0)
if (matches(curr, binary(LtU, any(&x), ival(&c))) &&
if (curr->op == Abstract::getBinary(curr->left->type, Abstract::LtU) &&
(c = getFallthrough(curr->right)->dynCast<Const>()) &&
c->value.isZero()) {
c->value = Literal::makeZero(Type::i32);
c->type = Type::i32;
return replaceCurrent(getDroppedChildrenAndAppend(curr, c));
// We could reuse c here, if we checked it had no more uses
auto zero =
Builder(*getModule()).makeConst(Literal::makeZero(Type::i32));
return replaceCurrent(getDroppedChildrenAndAppend(curr, zero));
}
}
}
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66 changes: 66 additions & 0 deletions test/lit/passes/optimize-instructions-mvp.wast
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Original file line number Diff line number Diff line change
Expand Up @@ -175,6 +175,7 @@
)
)
)

;; CHECK: (func $eqz-gt_s (result i32)
;; CHECK-NEXT: (i32.eqz
;; CHECK-NEXT: (i32.const 0)
Expand Down Expand Up @@ -11531,6 +11532,44 @@
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (block (result i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.load
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (block (result i32)
;; CHECK-NEXT: (i32.store
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (block (result i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i64.load
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (block (result i64)
;; CHECK-NEXT: (i64.store
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i64.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i64.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.ne
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 0)
Expand Down Expand Up @@ -11803,6 +11842,33 @@
)
(i64.const 0)
))
(drop (i32.lt_u
(i32.load
(i32.const 0)
)
(block (result i32)
(i32.store
(i32.const 0)
(i32.const 0)
)
(i32.const 0)
)
)
)
(drop (i64.lt_u
(i64.load
(i32.const 0)
)
(block (result i64)
(i64.store
(i32.const 0)
(i64.const 0)
)
(i64.const 0)
)
)
)


;; (unsigned)x > 0 => x != 0
(drop (i32.gt_u
Expand Down
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