https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115262
--- Comment #2 from Peter Bergner <bergner at gcc dot gnu.org> --- (In reply to Jeffrey A. Law from comment #1) > It looks like the test wants to see xxsel, but after that change we get > xxlor and what looks like a slight difference in register allocation. I > can't really judge if the new code is better, worse is equivalent. xxsel XT,XA,XB,XC computes XT = (XA & ~XC) | (XB & XC). Using De Morgan's law given XB == XC, that seems to simplify to XT = XA | XB which is what you're producing and an xxlor (a simple logical or) is not going to be slower than a xxsel and is probably faster. I agree with Bill that this looks like an example of needing to update the expected results of the test case. I'll let Segher and/or Ke Wen comment though.
