https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55278
--- Comment #28 from Uroš Bizjak <ubizjak at gmail dot com> --- (In reply to Jakub Jelinek from comment #12) > (force gcc to avoid xorw memory, %hireg and instead use movzwl memory, > %sireg; ... xorl %sireg, %sireg2) and p2 was something similar for *xorqi_1. > > Looking at icc generated assembly, it is interesting to see that the only > HImode instructions it ever uses are rolw and movw stores, for everything > else it uses > movzwl loads and SImode arithmetics (well, I guess shift right > shrw/sarw/rorw can't be avoided either). Similarly, icc on the testcase > doesn't emit any QImode instructions at all, while gcc emits tons of them > and llvm something in between. -mtune-ctrl=^himode_math,^qimode_math will eliminate all HImode and QImode arithmetics.
