Fix block-nested Pop in GUFA#8747
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In GUFA, when optimizing RefEq or RefTest expressions, they are replaced by constants if the optimizer can prove the two sides have no intersection. However, if the expression contains side effects (like a Pop), getDroppedChildrenAndAppend is used to preserve them, which wraps the side-effect expressions in a Block. If the Pop is nested inside this Block, it becomes invalidly nested within the catch block, which violates validation rules. GUFA has a fixup pass (EHUtils::handleBlockNestedPops) designed to fix this by spilling the Pop to a local, but it was not being run because visitRefEq and visitRefTest failed to set the `optimized = true` flag. Fix the issue by setting `optimized = true` when RefEq or RefTest are optimized, ensuring the post-optimization cleanups (including the nested pop fixup) are executed. Add a regression test to gufa-cast-all.wast.
| auto* result = Builder(*getModule()).makeConst(Literal(int32_t(0))); | ||
| replaceCurrent(getDroppedChildrenAndAppend( | ||
| curr, *getModule(), getPassOptions(), result)); | ||
| optimized = true; |
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This pass has an override for replaceCurrent, I wonder if we should have that method set optimized by default so that we don't forget other cases? It seems like after this PR, all usages of replaceCurrent set optimized to true. I don't have a strong opinion, I can imagine there might be cases where we don't want to set it to true unintentionally too.
stevenfontanella
approved these changes
May 21, 2026
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In GUFA, when optimizing RefEq or RefTest expressions, they are replaced by constants if the optimizer can prove the two sides have no intersection. However, if the expression contains side effects (like a Pop), getDroppedChildrenAndAppend is used to preserve them, which wraps the side-effect expressions in a Block.
If the Pop is nested inside this Block, it becomes invalidly nested within the catch block, which violates validation rules. GUFA has a fixup pass (EHUtils::handleBlockNestedPops) designed to fix this by spilling the Pop to a local, but it was not being run because visitRefEq and visitRefTest failed to set the
optimized = trueflag.Fix the issue by setting
optimized = truewhen RefEq or RefTest are optimized, ensuring the post-optimization cleanups (including the nested pop fixup) are executed.Add a regression test to gufa-cast-all.wast.