https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79389
--- Comment #8 from Uroš Bizjak <ubizjak at gmail dot com> --- (In reply to Jakub Jelinek from comment #6) > Well, at least in the -O2 case, it clearly shows that (RTL) if-conversion > does happen. > If SETCC + ZEXT + ADD is always a win compared to LEAL x+1 + CMOV*, then we > should just expand the cmov in that case to that or combine or peephole it > to that. > Now, with -m32 -march=i586 -O2 (so that cmov can't be used), I see > noce_try_addcc (which is exactly that, SETCC + ZEXT + ADD) fails because the > condition is complex: > (ne (and:QI (subreg:QI (zero_extract:SI (reg:HI 100) > (const_int 8 [0x8]) > (const_int 8 [0x8])) 0) > (const_int 5 [0x5])) > (const_int 0 [0])) You can use -march=i686, so fcomi will be emitted instead of fcomp/fnstsw/test.
