http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49468
--- Comment #1 from Oleg Endo <oleg.e...@t-online.de> 2011-06-19 15:29:45 UTC --- Created attachment 24560 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24560 Proposed patch The patch adds explicit handling of abs:SI and abs:DI to the machine description instead of relying on the default abs handling. On SH4 the zero-offset branch way is definitely faster. It reduces pressure on EX group instructions and improves parallel instruction execution. On other than SH4 zero-offset branches are not as fast, but the resulting code should still be faster than the default branch-free abs code, at least it is more compact. The patch also handles the case of neg (abs (...)) by simply inverting the branch condition. Feedback appreciated.
