diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/passes/RemoveUnusedBrs.cpp | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp index 5631c9d5f..157cfc1f3 100644 --- a/src/passes/RemoveUnusedBrs.cpp +++ b/src/passes/RemoveUnusedBrs.cpp @@ -97,6 +97,12 @@ static bool tooCostlyToRunUnconditionally(const PassOptions& passOptions, return total >= TOO_MUCH; } +static bool canEmitSelectWithArms(Expression* ifTrue, Expression* ifFalse) { + // A select only allows a single value in its arms in the spec: + // https://webassembly.github.io/spec/core/valid/instructions.html#xref-syntax-instructions-syntax-instr-parametric-mathsf-select-t-ast + return ifTrue->type.isSingle() && ifFalse->type.isSingle(); +} + struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> { bool isFunctionParallel() override { return true; } @@ -1023,7 +1029,8 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> { EffectAnalyzer(passOptions, features, curr) .hasSideEffects(); list[0] = old; - if (canReorder && !hasSideEffects) { + if (canReorder && !hasSideEffects && + canEmitSelectWithArms(br->value, curr)) { ExpressionManipulator::nop(list[0]); replaceCurrent( builder.makeSelect(br->condition, br->value, curr)); @@ -1044,8 +1051,11 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> { // Convert an if into a select, if possible and beneficial to do so. Select* selectify(If* iff) { - if (!iff->ifFalse || !iff->ifTrue->type.isSingle() || - !iff->ifFalse->type.isSingle()) { + // Only an if-else can be turned into a select. + if (!iff->ifFalse) { + return nullptr; + } + if (!canEmitSelectWithArms(iff->ifTrue, iff->ifFalse)) { return nullptr; } if (iff->condition->type == Type::unreachable) { |