153897 2016-02-04 15:05:07 -0800 REGRESSION(192409): Cannot rely on add32() to zero-extend 2016-02-04 15:23:58 -0800 1 1 1 Unclassified WebKit JavaScriptCore WebKit Nightly Build All All RESOLVED FIXED P2 Normal --- 1 fpizlo webkit-unassigned oldest_to_newest 1162207 0 fpizlo 2016-02-04 15:05:07 -0800 Callers of add32() and other 32-bit arithmetic ops rely on the fact that the destination register is zero-extended. The optimizations in r192409 broke this feature, and this causes crashes on some obscure code. 1162212 1 fpizlo 2016-02-04 15:16:34 -0800 rdar://problem/24289839 1162213 2 fpizlo 2016-02-04 15:20:26 -0800 I tried writing a test, but actually hitting this issue is sooooper hard. 1162216 3 fpizlo 2016-02-04 15:23:58 -0800 Landed in http://trac.webkit.org/changeset/196152