[Bug target/50131] Optimize x = -1 with "or" for -O

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50131 Andrew Pinski changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed|

[Bug target/50131] Optimize x = -1 with "or" for -O

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50131 H.J. Lu changed: What|Removed |Added CC||sergos.gnu at gmail dot com --- Comment #5 from

[Bug target/50131] Optimize x = -1 with "or" for -O

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50131 --- Comment #4 from Richard Guenther 2011-08-21 09:19:28 UTC --- I'm sure or $-1,reg doesn't avoid the data dependence on reg and may even result in hitting partial reg stall issues. Surely xor reg,reg; not reg might be another alternative?

[Bug target/50131] Optimize x = -1 with "or" for -O

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50131 --- Comment #3 from H.J. Lu 2011-08-20 19:44:49 UTC --- (In reply to comment #2) > Is or $-1, reg on all CPUs equally expensive to mov $-1, reg though (as or > generally needs the previous reg content while mov does not; I know some CPUs > specia

[Bug target/50131] Optimize x = -1 with "or" for -O

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50131 Jakub Jelinek changed: What|Removed |Added CC||jakub at gcc dot gnu.org --- Comment #2 f

[Bug target/50131] Optimize x = -1 with "or" for -O

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50131 --- Comment #1 from H.J. Lu 2011-08-19 20:58:00 UTC --- There are 1273 "movl $0x," and 924 "movq 0x," in cc1plus. This change can reduce cc1plus size by 6242 bytes.