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Merged
tlively merged 2 commits into from
Sep 17, 2026
+140 −27
Merged

[TailCall] Fix intrinsic and unreachable calls #9111

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7b3e7d1
[TailCall] Fix intrinsic and unreachable calls
tlively Sep 17, 2026
6a21322
Update test/lit/passes/tail-call.wast
tlively Sep 17, 2026
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6 changes: 4 additions & 2 deletions src/passes/Intrinsics.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -39,9 +39,11 @@ struct IntrinsicLowering : public WalkerPass<PostWalker<IntrinsicLowering>> {
// forgets to optimize.
Builder builder(*getModule());
if (auto* refFunc = target->dynCast<RefFunc>()) {
replaceCurrent(builder.makeCall(refFunc->func, operands, curr->type));
replaceCurrent(builder.makeCall(
refFunc->func, operands, curr->type, curr->isReturn));
} else {
replaceCurrent(builder.makeCallRef(target, operands, curr->type));
replaceCurrent(
builder.makeCallRef(target, operands, curr->type, curr->isReturn));
}
}
}
Expand Down
6 changes: 4 additions & 2 deletions src/passes/TailCall.cpp
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Expand Up @@ -205,8 +205,10 @@ struct TailCall : public WalkerPass<PreWalker<TailCall>> {
template<typename CallType> void handleCall(CallType* call, bool isTail) {
// A call in tail position can have a type incompatible with the function's
// return type if it is dead code at the end of a block following an earlier
// unreachable instruction.
if (call->isReturn || !isTail ||
// unreachable instruction. Also avoid optimizing unreachable calls (e.g.
// calls with unreachable operands), since their callee return type may not
// match the caller return type.
if (call->isReturn || !isTail || call->type == Type::unreachable ||
!Type::isSubType(call->type, getFunction()->getResults())) {
return;
}
Expand Down
26 changes: 21 additions & 5 deletions test/lit/passes/intrinsic-lowering.wast
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Expand Up @@ -6,18 +6,18 @@
(type $none (func))

;; call.without.effects with no params.
;; CHECK: (import "binaryen-intrinsics" "call.without.effects" (func $cwe-v (type $1) (param funcref) (result i32)))
;; CHECK: (import "binaryen-intrinsics" "call.without.effects" (func $cwe-v (type $3) (param funcref) (result i32)))
(import "binaryen-intrinsics" "call.without.effects" (func $cwe-v (param funcref) (result i32)))

;; call.without.effects with some params.
;; CHECK: (import "binaryen-intrinsics" "call.without.effects" (func $cwe-dif (type $2) (param f64 i32 funcref) (result f32)))
;; CHECK: (import "binaryen-intrinsics" "call.without.effects" (func $cwe-dif (type $4) (param f64 i32 funcref) (result f32)))
(import "binaryen-intrinsics" "call.without.effects" (func $cwe-dif (param f64) (param i32) (param funcref) (result f32)))

;; call.without.effects with no result.
;; CHECK: (import "binaryen-intrinsics" "call.without.effects" (func $cwe-n (type $3) (param funcref)))
;; CHECK: (import "binaryen-intrinsics" "call.without.effects" (func $cwe-n (type $5) (param funcref)))
(import "binaryen-intrinsics" "call.without.effects" (func $cwe-n (param funcref)))

;; CHECK: (func $test (type $4) (param $none (ref null $none))
;; CHECK: (func $test (type $1) (param $none (ref null $none))
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (call $make-i32)
;; CHECK-NEXT: )
Expand All @@ -39,7 +39,7 @@
(call $cwe-n (local.get $none))
)

;; CHECK: (func $make-i32 (type $5) (result i32)
;; CHECK: (func $make-i32 (type $2) (result i32)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
(func $make-i32 (result i32)
Expand All @@ -53,4 +53,20 @@
;; Helper function for the above.
(unreachable)
)

;; CHECK: (func $test-return-call (type $2) (result i32)
;; CHECK-NEXT: (return_call $make-i32)
;; CHECK-NEXT: )
(func $test-return-call (result i32)
(return_call $cwe-v (ref.func $make-i32))
)

;; CHECK: (func $test-return-call-ref (type $1) (param $none (ref null $none))
;; CHECK-NEXT: (return_call_ref $none
;; CHECK-NEXT: (local.get $none)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $test-return-call-ref (param $none (ref null $none))
(return_call $cwe-n (local.get $none))
)
)
129 changes: 111 additions & 18 deletions test/lit/passes/tail-call.wast
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Original file line number Diff line number Diff line change
Expand Up @@ -6,11 +6,16 @@
(module
;; CHECK: (type $none-to-i32 (func (result i32)))

;; CHECK: (type $i32-to-none (func (param i32)))

;; CHECK: (type $none-to-none (func))
(type $none-to-none (func))
(type $none-to-i32 (func (result i32)))
(type $i32-to-none (func (param i32)))
;; CHECK: (type $struct (sub (struct)))
(type $struct (sub (struct)))
;; CHECK: (import "binaryen-intrinsics" "call.without.effects" (func $cwe (type $6) (param i32 funcref) (result i32)))
(import "binaryen-intrinsics" "call.without.effects" (func $cwe (param i32) (param funcref) (result i32)))
;; CHECK: (global $g (mut i32) (i32.const 0))
(global $g (mut i32) (i32.const 0))
;; CHECK: (table $table 1 funcref)
Expand All @@ -19,6 +24,15 @@
;; CHECK: (func $void-callee (type $none-to-none)
;; CHECK-NEXT: )
(func $void-callee)
;; CHECK: (func $void-arg-callee (type $i32-to-none) (param $x i32)
;; CHECK-NEXT: )
(func $void-arg-callee (param $x i32))
;; CHECK: (func $i32-to-i32-callee (type $2) (param $x i32) (result i32)
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: )
(func $i32-to-i32-callee (param $x i32) (result i32)
(local.get $x)
)
;; CHECK: (func $value-callee (type $none-to-i32) (result i32)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
Expand All @@ -31,7 +45,7 @@
(func $ref-callee (result i32)
(i32.const 2)
)
;; CHECK: (func $param-callee (type $6) (param $x i32) (param $y i32) (result i32)
;; CHECK: (func $param-callee (type $7) (param $x i32) (param $y i32) (result i32)
;; CHECK-NEXT: (i32.add
;; CHECK-NEXT: (local.get $x)
;; CHECK-NEXT: (local.get $y)
Expand All @@ -43,7 +57,7 @@
(local.get $y)
)
)
;; CHECK: (func $subtype-callee (type $7) (result (ref $struct))
;; CHECK: (func $subtype-callee (type $8) (result (ref $struct))
;; CHECK-NEXT: (struct.new_default $struct)
;; CHECK-NEXT: )
(func $subtype-callee (result (ref $struct))
Expand Down Expand Up @@ -93,7 +107,7 @@
)
)

;; CHECK: (func $call-with-params (type $1) (param $x i32) (result i32)
;; CHECK: (func $call-with-params (type $2) (param $x i32) (result i32)
;; CHECK-NEXT: (return
;; CHECK-NEXT: (return_call $param-callee
;; CHECK-NEXT: (local.get $x)
Expand Down Expand Up @@ -123,7 +137,7 @@
)
)

;; CHECK: (func $subtype-return (type $8) (result anyref)
;; CHECK: (func $subtype-return (type $9) (result anyref)
;; CHECK-NEXT: (return_call $subtype-callee)
;; CHECK-NEXT: )
(func $subtype-return (result anyref)
Expand All @@ -140,7 +154,7 @@
(call $multivalue-callee)
)

;; CHECK: (func $conditional (type $1) (param $condition i32) (result i32)
;; CHECK: (func $conditional (type $2) (param $condition i32) (result i32)
;; CHECK-NEXT: (if
;; CHECK-NEXT: (local.get $condition)
;; CHECK-NEXT: (then
Expand All @@ -164,7 +178,7 @@
)
)

;; CHECK: (func $one-armed-if (type $3) (param $condition i32)
;; CHECK: (func $one-armed-if (type $i32-to-none) (param $condition i32)
;; CHECK-NEXT: (if
;; CHECK-NEXT: (local.get $condition)
;; CHECK-NEXT: (then
Expand Down Expand Up @@ -207,7 +221,7 @@
)
)

;; CHECK: (func $break (type $1) (param $condition i32) (result i32)
;; CHECK: (func $break (type $2) (param $condition i32) (result i32)
;; CHECK-NEXT: (block $out
;; CHECK-NEXT: (if
;; CHECK-NEXT: (local.get $condition)
Expand All @@ -234,7 +248,7 @@
)
)

;; CHECK: (func $return-break (type $1) (param $condition i32) (result i32)
;; CHECK: (func $return-break (type $2) (param $condition i32) (result i32)
;; CHECK-NEXT: (return
;; CHECK-NEXT: (block $out
;; CHECK-NEXT: (if
Expand Down Expand Up @@ -265,7 +279,7 @@
)
)

;; CHECK: (func $br-if-tail (type $1) (param $condition i32) (result i32)
;; CHECK: (func $br-if-tail (type $2) (param $condition i32) (result i32)
;; CHECK-NEXT: (block $out
;; CHECK-NEXT: (block
;; CHECK-NEXT: (return_call $value-callee)
Expand All @@ -287,7 +301,7 @@
)
)

;; CHECK: (func $br-if-not-tail (type $1) (param $condition i32) (result i32)
;; CHECK: (func $br-if-not-tail (type $2) (param $condition i32) (result i32)
;; CHECK-NEXT: (block $out (result i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (br_if $out
Expand Down Expand Up @@ -340,7 +354,7 @@
)
)

;; CHECK: (func $br-table-all-tail (type $1) (param $idx i32) (result i32)
;; CHECK: (func $br-table-all-tail (type $2) (param $idx i32) (result i32)
;; CHECK-NEXT: (block $out1
;; CHECK-NEXT: (block $out2
;; CHECK-NEXT: (block
Expand All @@ -364,7 +378,7 @@
)
)

;; CHECK: (func $br-table-not-all-tail (type $1) (param $idx i32) (result i32)
;; CHECK: (func $br-table-not-all-tail (type $2) (param $idx i32) (result i32)
;; CHECK-NEXT: (block $exit (result i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (block $not-exit (result i32)
Expand Down Expand Up @@ -392,7 +406,7 @@
)
)

;; CHECK: (func $void-break (type $3) (param $condition i32)
;; CHECK: (func $void-break (type $i32-to-none) (param $condition i32)
;; CHECK-NEXT: (block $out
;; CHECK-NEXT: (if
;; CHECK-NEXT: (local.get $condition)
Expand All @@ -419,7 +433,7 @@
)
)

;; CHECK: (func $void-br-if-tail (type $3) (param $condition i32)
;; CHECK: (func $void-br-if-tail (type $i32-to-none) (param $condition i32)
;; CHECK-NEXT: (block $out
;; CHECK-NEXT: (return_call $void-callee)
;; CHECK-NEXT: (br_if $out
Expand All @@ -438,7 +452,7 @@
)
)

;; CHECK: (func $void-br-if-not-tail (type $3) (param $condition i32)
;; CHECK: (func $void-br-if-not-tail (type $i32-to-none) (param $condition i32)
;; CHECK-NEXT: (block $out
;; CHECK-NEXT: (call $void-callee)
;; CHECK-NEXT: (br_if $out
Expand All @@ -459,7 +473,7 @@
)
)

;; CHECK: (func $void-br-table-all-tail (type $3) (param $idx i32)
;; CHECK: (func $void-br-table-all-tail (type $i32-to-none) (param $idx i32)
;; CHECK-NEXT: (block $out1
;; CHECK-NEXT: (block $out2
;; CHECK-NEXT: (return_call $void-callee)
Expand All @@ -482,7 +496,7 @@
)
)

;; CHECK: (func $void-br-table-not-all-tail (type $3) (param $idx i32)
;; CHECK: (func $void-br-table-not-all-tail (type $i32-to-none) (param $idx i32)
;; CHECK-NEXT: (block $exit
;; CHECK-NEXT: (block $not-exit
;; CHECK-NEXT: (call $void-callee)
Expand All @@ -507,7 +521,7 @@
)
)

;; CHECK: (func $loop-tail (type $1) (param $condition i32) (result i32)
;; CHECK: (func $loop-tail (type $2) (param $condition i32) (result i32)
;; CHECK-NEXT: (loop $l
;; CHECK-NEXT: (br_if $l
;; CHECK-NEXT: (local.get $condition)
Expand Down Expand Up @@ -579,4 +593,83 @@
(call $void-callee)
)
)

;; CHECK: (func $unreachable-arg-mismatched-call (type $none-to-i32) (result i32)
;; CHECK-NEXT: (call $void-arg-callee
;; CHECK-NEXT: (unreachable)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $unreachable-arg-mismatched-call (result i32)
;; Unreachable calls (e.g. due to an unreachable operand) are not converted
;; to return calls, avoiding return type mismatches and optimizing dead code.
(call $void-arg-callee
(unreachable)
)
)

;; CHECK: (func $unreachable-arg-matching-call (type $none-to-i32) (result i32)
;; CHECK-NEXT: (call $param-callee
;; CHECK-NEXT: (unreachable)
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $unreachable-arg-matching-call (result i32)
(call $param-callee
(unreachable)
(i32.const 1)
)
)

;; CHECK: (func $unreachable-arg-mismatched-call-indirect (type $none-to-i32) (result i32)
;; CHECK-NEXT: (call_indirect $table (type $i32-to-none)
;; CHECK-NEXT: (unreachable)
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $unreachable-arg-mismatched-call-indirect (result i32)
(call_indirect $table (type $i32-to-none)
(unreachable)
(i32.const 0)
)
)

;; CHECK: (func $unreachable-arg-mismatched-call-ref (type $10) (param $f (ref $i32-to-none)) (result i32)
;; CHECK-NEXT: (call_ref $i32-to-none
;; CHECK-NEXT: (unreachable)
;; CHECK-NEXT: (local.get $f)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $unreachable-arg-mismatched-call-ref (param $f (ref $i32-to-none)) (result i32)
(call_ref $i32-to-none
(unreachable)
(local.get $f)
)
)

;; CHECK: (func $unreachable-arg-mismatched-cwe (type $none-to-i32) (result i32)
;; CHECK-NEXT: (call $cwe
;; CHECK-NEXT: (unreachable)
;; CHECK-NEXT: (ref.func $void-arg-callee)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $unreachable-arg-mismatched-cwe (result i32)
(call $cwe
(unreachable)
(ref.func $void-arg-callee)
)
)

;; CHECK: (func $tail-cwe (type $none-to-i32) (result i32)
;; CHECK-NEXT: (return_call $cwe
;; CHECK-NEXT: (i32.const 42)
;; CHECK-NEXT: (ref.func $i32-to-i32-callee)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $tail-cwe (result i32)
;; call.without.effects is optimized when reachable.
(call $cwe
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(i32.const 42)
(ref.func $i32-to-i32-callee)
)
)
)
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