Bug 169250
| Summary: | LowerToAir should recognize subwidth variants of Equal(StrongCAS...) | ||
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| Product: | WebKit | Reporter: | Filip Pizlo <fpizlo> |
| Component: | JavaScriptCore | Assignee: | Nobody <webkit-unassigned> |
| Status: | NEW | ||
| Severity: | Normal | ||
| Priority: | P2 | ||
| Version: | WebKit Nightly Build | ||
| Hardware: | All | ||
| OS: | All | ||
Filip Pizlo
We currently don't turn Equal(StrongCAS...) into a direct branch on the CAS result for Width8 and Width16. We can do it. We'd have to match patterns like:
Equal(SExt8(StrongCAS(@exp, ...)), SExt8(@exp))
and
Equal(SExt8(StrongCAS(BitAnd(@exp, 0xff), ...)), SExt8(@exp))
Where the right-hand SExt8 is matched with sharing.
It's not super obvious how profitable this optimization will be, particularly if we have any optimizations that turn strong CAS into weak CAS.
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