http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53266
--- Comment #2 from Daniel Richard G. <skunk at iskunk dot org> 2012-05-07 17:42:43 UTC --- (In reply to comment #1) > mulhwu is a powerpc but not rs6000 instruction. When a file failed to compile, I noticed that specifying -mcpu=powerpc got things going again. I'm not clear on how GCC distinguishes powerpc versus rs6000, but as far as -mcpu is concerned, the former value seems to exclude mulhwu.