http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56695
--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> 2013-03-26 16:20:39 UTC --- (In reply to comment #6) > Created attachment 29733 [details] > Untested patch > > I was thinking about something like this. In 4.8, I added vec_cond_expr > expansion when the condition is not a comparison but a signed integer. I > didn't > notice that the vectorizer was generating comparisons with an unsigned result. > In 4.9 I added some folding of vec_cond_expr, which ended up folding the > comparison to a constant (still unsigned) and now cannot be expanded. What I > do > in the patch is make the vectorizer generate a signed result. An alternative > would be to change the decision that vec_cond_expr expects a signed first > argument. Ah, yes, that's nice. Thanks for explanation. BTW, it passes make RUNTESTFLAGS=vect.exp check-gcc. > Note as well that we reach expand with a vec_cond_expr with 3 constant > arguments, so there is a missed optimization there. Yep. Maybe something for fold_ternary?
