On Tue, Oct 25, 2011 at 4:28 AM, Bingfeng Mei <b...@broadcom.com> wrote: > Thanks, Andrew. I also implemented a quick patch on our port (based on GCC > 4.5). > I noticed it produced better code now for our applications. Maybe eliminating > control flow in earlier stage helps other optimizing passes. Currently, tree > if-conversion pass is not turned on by default (only with tree vectorization > or some other passes). Maybe it is worth to make it default at -O2 (for those > processors support conditional move)?
I just committed the patch which does the expansion of COND_EXPR to condmov to the trunk. I have more patches which do what ifcvt does but in phiopt (which seems better in general as ifcvt work only over loops). I hope to post those patches in the coming weeks. Thanks, Andrew Pinski > > Cheers, > Bingfeng > >> -----Original Message----- >> From: Andrew Pinski [mailto:pins...@gmail.com] >> Sent: 24 October 2011 17:20 >> To: Richard Guenther >> Cc: Bingfeng Mei; gcc@gcc.gnu.org >> Subject: Re: Why doesn't GCC generate conditional move for COND_EXPR? >> >> On Mon, Oct 24, 2011 at 7:00 AM, Richard Guenther >> <richard.guent...@gmail.com> wrote: >> > On Mon, Oct 24, 2011 at 2:55 PM, Bingfeng Mei <b...@broadcom.com> >> wrote: >> >> Hello, >> >> I noticed that COND_EXPR is not expanded to conditional move >> >> as MIN_EXPR/MAX_EXPR are (assuming movmodecc is available). >> >> I wonder why not? >> >> >> >> I have some loop that fails tree vectorization, but still contains >> >> COND_EXPR from tree ifcvt pass. In the end, the generated code >> >> is worse than if I don't turned -ftree-vectorize on. This >> >> is on our private port. >> > >> > Because nobody touched COND_EXPR expansion since ages. >> >> I have a patch which I will be submitting next week or so that does >> this expansion correctly. In fact I have a few patches which improves >> the generation of COND_EXPR in simple cases (in PHI-OPT). >> >> Thanks, >> Andrew Pinski >
