http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47000
--- Comment #26 from Jan Hubicka <hubicka at gcc dot gnu.org> 2010-12-21 10:39:42 UTC --- Hi, I read the comment only after comiting the patch. We generally believe conversions to be free even if this is not always the case. FP->int conversions tends to be expensive, too. I don't think it is serious problem since the conversions tends to be dominated by real work elsewhere and there is good chance for conversions to combine and optimize when code is duplicated by inlining or peeling or so. For non-registers V_C_Es are already counted as all non-register accesses are believed to be read/writes. So all we get wrong are those int<->fp V_C_Es. I don't think they are terribly common and it is very target specific on how expensive they really are... SSE intrincics and SRA are nowdays both quite good source of V_C_Es that are cheap so I would guess that wast majority of them is cheap anyway. Honza
