169250 2017-03-06 20:02:31 -0800 LowerToAir should recognize subwidth variants of Equal(StrongCAS...) 2017-03-06 20:02:31 -0800 1 1 1 Unclassified WebKit JavaScriptCore WebKit Nightly Build All All NEW P2 Normal --- 1 fpizlo webkit-unassigned oldest_to_newest 1284143 0 fpizlo 2017-03-06 20:02:31 -0800 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.