diff options
| -rw-r--r-- | src/passes/CodePushing.cpp | 20 | ||||
| -rw-r--r-- | test/lit/passes/code-pushing_tnh.wast | 30 |
2 files changed, 49 insertions, 1 deletions
diff --git a/src/passes/CodePushing.cpp b/src/passes/CodePushing.cpp index 20f16b145..2b45dda16 100644 --- a/src/passes/CodePushing.cpp +++ b/src/passes/CodePushing.cpp @@ -323,6 +323,26 @@ private: assert(i > 0); i--; auto* pushable = isPushable(list[i]); + if (pushable && pushable->type == Type::unreachable) { + // Don't try to push something unreachable. If we did, then we'd need to + // refinalize the block we are moving it from: + // + // (block $unreachable + // (local.set $x (unreachable)) + // (if (..) + // (.. (local.get $x)) + // ) + // + // The block should not be unreachable if the local.set is moved into + // the if arm (the if arm may not execute, so the if itself will not + // change type). It is simpler to avoid this complexity and leave this + // to DCE to simplify first. + // + // (Note that the side effect of trapping will normally prevent us from + // trying to push something unreachable, but in traps-never-happen mode + // we are allowed to ignore that, and so we need this check.) + pushable = nullptr; + } if (!pushable) { // Something that is staying where it is, so anything we push later must // move past it. Note the effects and continue. diff --git a/test/lit/passes/code-pushing_tnh.wast b/test/lit/passes/code-pushing_tnh.wast index 9993c686b..17f69a466 100644 --- a/test/lit/passes/code-pushing_tnh.wast +++ b/test/lit/passes/code-pushing_tnh.wast @@ -6,6 +6,8 @@ (module ;; CHECK: (type $i32_i32_=>_none (func (param i32 i32))) + ;; CHECK: (type $none_=>_none (func)) + ;; CHECK: (func $div (param $x i32) (param $y i32) ;; CHECK-NEXT: (local $temp i32) ;; CHECK-NEXT: (block $block @@ -44,5 +46,31 @@ ) ) ) -) + ;; CHECK: (func $unreachable-value + ;; CHECK-NEXT: (local $x i32) + ;; CHECK-NEXT: (local.tee $x + ;; CHECK-NEXT: (unreachable) + ;; CHECK-NEXT: ) + ;; CHECK-NEXT: (if + ;; CHECK-NEXT: (i32.const 0) + ;; CHECK-NEXT: (drop + ;; CHECK-NEXT: (local.get $x) + ;; CHECK-NEXT: ) + ;; CHECK-NEXT: ) + ;; CHECK-NEXT: ) + (func $unreachable-value + (local $x i32) + ;; We should not push this into the if. (If we did, we'd need to refinalize + ;; the block, or we'd error; instead, leave this to DCE.) + (local.set $x + (unreachable) + ) + (if + (i32.const 0) + (drop + (local.get $x) + ) + ) + ) +) |