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Fix missing unreachable checks in Heap2Local visitStructRMW/visitStructCmpxchg #8304

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Merged
kripken merged 1 commit into from
Feb 12, 2026
Merged

Fix missing unreachable checks in Heap2Local visitStructRMW/visitStructCmpxchg #8304

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10 changes: 10 additions & 0 deletions src/passes/Heap2Local.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1038,6 +1038,11 @@ struct Struct2Local : PostWalker<Struct2Local> {
return;
}

if (curr->type == Type::unreachable) {
// As with RefGetDesc and StructGet, above.
return;
}

[[maybe_unused]] auto& field = fields[curr->index];
auto type = curr->type;
assert(type == field.type);
Expand Down Expand Up @@ -1108,6 +1113,11 @@ struct Struct2Local : PostWalker<Struct2Local> {
return;
}

if (curr->type == Type::unreachable) {
// As with RefGetDesc and StructGet, above.
return;
}

[[maybe_unused]] auto& field = fields[curr->index];
auto type = curr->type;
assert(type == field.type);
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57 changes: 57 additions & 0 deletions test/lit/passes/heap2local-rmw.wast
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Expand Up @@ -693,4 +693,61 @@
(i32.const 2)
)
)

;; CHECK: (func $rmw-unreachable-value (type $1) (result i32)
;; CHECK-NEXT: (local $0 i32)
;; CHECK-NEXT: (block ;; (replaces unreachable StructRMW we can't emit)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (block (result nullref)
;; CHECK-NEXT: (local.set $0
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: (ref.null none)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (unreachable)
;; CHECK-NEXT: )
;; CHECK-NEXT: (unreachable)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $rmw-unreachable-value (result i32)
;; When the value is unreachable, the whole expression is unreachable.
;; We should not attempt to optimize this (it would hit an assertion
;; on type == field.type since unreachable != i32).
(struct.atomic.rmw.add $i32 0
(struct.new_default $i32)
(unreachable)
)
)

;; CHECK: (func $cmpxchg-unreachable-expected (type $1) (result i32)
;; CHECK-NEXT: (local $0 i32)
;; CHECK-NEXT: (block ;; (replaces unreachable StructCmpxchg we can't emit)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (block (result nullref)
;; CHECK-NEXT: (local.set $0
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: (ref.null none)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (unreachable)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (unreachable)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $cmpxchg-unreachable-expected (result i32)
;; When the expected operand is unreachable, the whole expression is
;; unreachable. We should not attempt to optimize this.
(struct.atomic.rmw.cmpxchg $i32 0
(struct.new_default $i32)
(unreachable)
(i32.const 1)
)
)
)
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