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Merged
kripken merged 7 commits into from
Sep 17, 2026
Merged

Mark atomic read-write etc. operations as generative #9112

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7a5b0ca
Add missing isGenerative data, and one test
kripken Sep 17, 2026
804e297
tests
kripken Sep 17, 2026
e330965
more
kripken Sep 17, 2026
971ee4b
more
kripken Sep 17, 2026
bf2e472
more
kripken Sep 17, 2026
9a61e8e
avoid fuzzing waitqueue
kripken Sep 17, 2026
bb62520
fix
kripken Sep 17, 2026
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1 change: 1 addition & 0 deletions scripts/test/fuzzing.py
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Expand Up @@ -117,6 +117,7 @@
# Not fully implemented.
'waitqueue.wast',
'gufa-waitqueue.wast',
'optimize-instructions-waitqueue.wast',
'publish.wast',
'optimize-instructions-publish.wast',
# TODO: fix handling of the non-utf8 names here
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18 changes: 16 additions & 2 deletions src/ir/properties.cpp
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Expand Up @@ -47,9 +47,23 @@ struct GenerativityScanner : public PostWalker<GenerativityScanner> {
void visitArrayNewElem(ArrayNewElem* curr) { generative = true; }
void visitArrayNewFixed(ArrayNewFixed* curr) { generative = true; }
void visitContNew(ContNew* curr) { generative = true; }

// Notifications/waits depend on events on other threads.
void visitAtomicNotify(AtomicNotify* curr) { generative = true; }
void visitWaitqueueNotify(WaitqueueNotify* curr) { generative = true; }
void visitAtomicWait(AtomicWait* curr) { generative = true; }
void visitStructWait(StructWait* curr) { generative = true; }
void visitWaitqueueNew(WaitqueueNew* curr) { generative = true; }
// TODO: waitqueue.notify, struct.wait, atomic.notify, and atomic.wait should
// also be generative.

// Instructions that both read and write memory are generative (as they
// themselves can lead to a different value being returned from identical-
// looking instructions; no other instruction in the middle is needed).
void visitAtomicRMW(AtomicRMW* curr) { generative = true; }
void visitAtomicCmpxchg(AtomicCmpxchg* curr) { generative = true; }
void visitStructRMW(StructRMW* curr) { generative = true; }
void visitStructCmpxchg(StructCmpxchg* curr) { generative = true; }
void visitArrayRMW(ArrayRMW* curr) { generative = true; }
void visitArrayCmpxchg(ArrayCmpxchg* curr) { generative = true; }
};

} // anonymous namespace
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148 changes: 148 additions & 0 deletions test/lit/passes/optimize-instructions-atomics.wast
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Expand Up @@ -91,4 +91,152 @@
;; skips
(drop (i64.extend_i32_s (i32.atomic.load (local.get $x))))
)

;; CHECK: (func $select-atomic-rmw (result i32)
;; CHECK-NEXT: (select
;; CHECK-NEXT: (i32.atomic.rmw16.xchg_u
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.atomic.rmw16.xchg_u
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $select-atomic-rmw (result i32)
;; The first rmw here influences the second, and we need to return the result
;; of the first, which means we need a temp local. We avoid adding one and do
;; not optimize here. Other instructions are tested in the functions below.
(select
(i32.atomic.rmw16.xchg_u
(i32.const 0)
(i32.const 1)
)
(i32.atomic.rmw16.xchg_u
(i32.const 0)
(i32.const 1)
)
(i32.const 1)
)
)

;; CHECK: (func $select-atomic-cmpxchg (result i32)
;; CHECK-NEXT: (select
;; CHECK-NEXT: (i32.atomic.rmw.cmpxchg
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: (i32.const 2)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.atomic.rmw.cmpxchg
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: (i32.const 2)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $select-atomic-cmpxchg (result i32)
(select
(i32.atomic.rmw.cmpxchg
(i32.const 0)
(i32.const 1)
(i32.const 2)
)
(i32.atomic.rmw.cmpxchg
(i32.const 0)
(i32.const 1)
(i32.const 2)
)
(i32.const 1)
)
)

;; CHECK: (func $select-atomic-wait (result i32)
;; CHECK-NEXT: (select
;; CHECK-NEXT: (memory.atomic.wait32
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: (i64.const 2)
;; CHECK-NEXT: )
;; CHECK-NEXT: (memory.atomic.wait32
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: (i64.const 2)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $select-atomic-wait (result i32)
(select
(memory.atomic.wait32
(i32.const 0)
(i32.const 1)
(i64.const 2)
)
(memory.atomic.wait32
(i32.const 0)
(i32.const 1)
(i64.const 2)
)
(i32.const 1)
)
)

;; CHECK: (func $select-atomic-notify (result i32)
;; CHECK-NEXT: (select
;; CHECK-NEXT: (memory.atomic.notify
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (memory.atomic.notify
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $select-atomic-notify (result i32)
(select
(memory.atomic.notify
(i32.const 0)
(i32.const 1)
)
(memory.atomic.notify
(i32.const 0)
(i32.const 1)
)
(i32.const 1)
)
)

;; CHECK: (func $select-atomic-load (result i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.atomic.load
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.atomic.load
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $select-atomic-load (result i32)
;; For comparison with above, when the instruction is not generative, we can
;; optimize: the two atomic loads must return the same thing, so we drop the
;; first and return the second (even though the first is what the select
;; returns).
(select
(i32.atomic.load
(i32.const 0)
)
(i32.atomic.load
(i32.const 0)
)
(i32.const 1)
)
)
)
132 changes: 130 additions & 2 deletions test/lit/passes/optimize-instructions-gc-atomics.wast
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Expand Up @@ -3,11 +3,12 @@
;; RUN: wasm-opt %s -all --optimize-instructions -S -o - | filecheck %s

(module
;; CHECK: (type $unshared (struct (field (mut i32))))

;; CHECK: (type $shared (shared (struct (field (mut i32)))))
(type $shared (shared (struct (field (mut i32)))))
;; CHECK: (type $unshared (struct (field (mut i32))))
(type $unshared (struct (field (mut i32))))
;; CHECK: (type $array (shared (array (mut i32))))
(type $array (shared (array (mut i32))))

;; CHECK: (func $get-unordered-unshared (type $2) (result i32)
;; CHECK-NEXT: (struct.get $unshared 0
Expand Down Expand Up @@ -154,4 +155,131 @@
(i32.const 0)
)
)

;; CHECK: (func $select-struct-rmw (type $4) (param $x (ref $shared)) (result i32)
;; CHECK-NEXT: (select
;; CHECK-NEXT: (struct.atomic.rmw.add $shared 0
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (struct.atomic.rmw.add $shared 0
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $select-struct-rmw (param $x (ref $shared)) (result i32)
;; The first rmw here influences the second, and we need to return the result
;; of the first, which means we need a temp local. We avoid adding one and do
;; not optimize here. Other instructions are tested in the functions below.
(select
(struct.atomic.rmw.add $shared 0
(local.get $x)
(i32.const 1)
)
(struct.atomic.rmw.add $shared 0
(local.get $x)
(i32.const 1)
)
(i32.const 1)
)
)

;; CHECK: (func $select-struct-cmpxchg (type $4) (param $x (ref $shared)) (result i32)
;; CHECK-NEXT: (select
;; CHECK-NEXT: (struct.atomic.rmw.cmpxchg $shared 0
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: (i32.const 2)
;; CHECK-NEXT: )
;; CHECK-NEXT: (struct.atomic.rmw.cmpxchg $shared 0
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: (i32.const 2)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $select-struct-cmpxchg (param $x (ref $shared)) (result i32)
(select
(struct.atomic.rmw.cmpxchg $shared 0
(local.get $x)
(i32.const 1)
(i32.const 2)
)
(struct.atomic.rmw.cmpxchg $shared 0
(local.get $x)
(i32.const 1)
(i32.const 2)
)
(i32.const 1)
)
)

;; CHECK: (func $select-array-rmw (type $6) (param $x (ref $array)) (result i32)
;; CHECK-NEXT: (select
;; CHECK-NEXT: (array.atomic.rmw.add $array
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (array.atomic.rmw.add $array
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $select-array-rmw (param $x (ref $array)) (result i32)
(select
(array.atomic.rmw.add $array
(local.get $x)
(i32.const 0)
(i32.const 1)
)
(array.atomic.rmw.add $array
(local.get $x)
(i32.const 0)
(i32.const 1)
)
(i32.const 1)
)
)

;; CHECK: (func $select-array-cmpxchg (type $6) (param $x (ref $array)) (result i32)
;; CHECK-NEXT: (select
;; CHECK-NEXT: (array.atomic.rmw.cmpxchg $array
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: (i32.const 2)
;; CHECK-NEXT: )
;; CHECK-NEXT: (array.atomic.rmw.cmpxchg $array
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: (i32.const 2)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $select-array-cmpxchg (param $x (ref $array)) (result i32)
(select
(array.atomic.rmw.cmpxchg $array
(local.get $x)
(i32.const 0)
(i32.const 1)
(i32.const 2)
)
(array.atomic.rmw.cmpxchg $array
(local.get $x)
(i32.const 0)
(i32.const 1)
(i32.const 2)
)
(i32.const 1)
)
)
)
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