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kripken
commented
Sep 25, 2026
| if (constraints.provesNothing()) { | ||
| setProvesNothing(index); | ||
| } else { | ||
| if (!constraints.provesNothing()) { |
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Drive-by fix, see the comment on line 1054 - we already prove nothing at this point.
kripken
commented
Sep 25, 2026
| // We just proved we are in unreachable code. | ||
| unreachable = true; | ||
| map.clear(); | ||
| refs.clear(); |
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Another drive-by trivial fix (irrelevent for correctness, see the comment on new line 1215).
kripken
commented
Sep 25, 2026
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| auto& refIndexes = iter->second; | ||
| auto refIndexes = std::move(iter->value); | ||
| refs.erase(iter); |
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(as above, we kept around stale refs unnecessarily; added a comment in the header to mention that this function is called when we wipe out all the info)
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We usually have only a few useful constraints, so the map is mostly
empty. An
unordered_mapis then pretty inefficient, and it is betterto use a vector. Sorting it makes lookup still pretty fast.
This especially helps in ORing two sets of constraints, as we can
just do an intersection (the OR result is only interesting if we had
something in both inputs - otherwise we can prove nothing), which
is efficient on sorted vectors.
To implement this, generalize the existing SortedVector.
This makes the pass 50% faster on average, though the spread
is wide (20%-almost 2X faster). I tested around 10 real-world
wasm files and did not see a single one with less than an 18%
speedup, and never a regression.