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Subject: Re: [PATCH] SIMD: Try without any CFLAGS before forcing -mcpu= Newsgroups: gmane.comp.graphics.pixman Date: Sunday 14th March 2010 17:25:10 UTC (over 7 years ago) On Wed, Mar 10, 2010, Siarhei Siamashka wrote: > I would prefer a bit more descriptive comment (with the details copied > from that launchpad page). I see you pushed this now; thanks! Yeah, it's not obvious why one needs to try with the toolchain defaults first. I'm attaching a patch to update the comments. > Patch looks mostly OK to me and improves arm simd support a bit. It still > fails with CFLAGS="-O2 -mthumb" (and toolchain configured to compile for armv4 > by default) This is unfortunate, but even if I could change the configure test to succeed here, the actual build would place CFLAGS last (user-overrides); it's perhaps best if the build fails at this point. The other option would be to munge the user-specific CFLAGS in configure, but I'm not sure I'm confortable with that, plus these can be overriden during the build as well. So I guess people forcing Thumb in CFLAGS with a default of an old CPU will have a bit more pain here. I think it also fails if you force -mcpu=oldcpu in CFLAGS. > But that was also happening earlier, so it is not a regression. Ack > In my opinion the best solution overall would be to move all the assembly > optimizations into separate .S files also for legacy ARM processors and > get rid of these compiler option hacks. I think that bringing support for > legacy ARM processors into a better shape is quite realistic even for 0.18.0 > stable release, which is due to be released this month. But it can only happen > if enough people are interested in this, and more importantly, are ready to > actively participate in testing. I think this should be kept as an open bug against pixman that the inline asm()s would better be written as separate .S files (thanks for the idea). -- Loïc Minier |
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