Ping...
On 06/01/17 18:01, Bernd Edlinger wrote: > Ping... > > On 05/12/17 18:49, Bernd Edlinger wrote: >> Ping... >> >> On 04/29/17 19:45, Bernd Edlinger wrote: >>> Ping... >>> >>> I attached a rebased version since there was a merge conflict in >>> the xordi3 pattern, otherwise the patch is still identical. >>> It splits adddi3, subdi3, anddi3, iordi3, xordi3 and one_cmpldi2 >>> early when the target has no neon or iwmmxt. >>> >>> >>> Thanks >>> Bernd. >>> >>> >>> >>> On 11/28/16 20:42, Bernd Edlinger wrote: >>>> On 11/25/16 12:30, Ramana Radhakrishnan wrote: >>>>> On Sun, Nov 6, 2016 at 2:18 PM, Bernd Edlinger >>>>> <bernd.edlin...@hotmail.de> wrote: >>>>>> Hi! >>>>>> >>>>>> This improves the stack usage on the sha512 test case for the case >>>>>> without hardware fpu and without iwmmxt by splitting all di-mode >>>>>> patterns right while expanding which is similar to what the >>>>>> shift-pattern >>>>>> does. It does nothing in the case iwmmxt and fpu=neon or vfp as >>>>>> well as >>>>>> thumb1. >>>>>> >>>>> >>>>> I would go further and do this in the absence of Neon, the VFP unit >>>>> being there doesn't help with DImode operations i.e. we do not have 64 >>>>> bit integer arithmetic instructions without Neon. The main reason why >>>>> we have the DImode patterns split so late is to give a chance for >>>>> folks who want to do 64 bit arithmetic in Neon a chance to make this >>>>> work as well as support some of the 64 bit Neon intrinsics which IIRC >>>>> map down to these instructions. Doing this just for soft-float doesn't >>>>> improve the default case only. I don't usually test iwmmxt and I'm not >>>>> sure who has the ability to do so, thus keeping this restriction for >>>>> iwMMX is fine. >>>>> >>>>> >>>> >>>> Yes I understand, thanks for pointing that out. >>>> >>>> I was not aware what iwmmxt exists at all, but I noticed that most >>>> 64bit expansions work completely different, and would break if we split >>>> the pattern early. >>>> >>>> I can however only look at the assembler outout for iwmmxt, and make >>>> sure that the stack usage does not get worse. >>>> >>>> Thus the new version of the patch keeps only thumb1, neon and iwmmxt as >>>> it is: around 1570 (thumb1), 2300 (neon) and 2200 (wimmxt) bytes stack >>>> for the test cases, and vfp and soft-float at around 270 bytes stack >>>> usage. >>>> >>>>>> It reduces the stack usage from 2300 to near optimal 272 bytes (!). >>>>>> >>>>>> Note this also splits many ldrd/strd instructions and therefore I >>>>>> will >>>>>> post a followup-patch that mitigates this effect by enabling the >>>>>> ldrd/strd >>>>>> peephole optimization after the necessary reg-testing. >>>>>> >>>>>> >>>>>> Bootstrapped and reg-tested on arm-linux-gnueabihf. >>>>> >>>>> What do you mean by arm-linux-gnueabihf - when folks say that I >>>>> interpret it as --with-arch=armv7-a --with-float=hard >>>>> --with-fpu=vfpv3-d16 or (--with-fpu=neon). >>>>> >>>>> If you've really bootstrapped and regtested it on armhf, doesn't this >>>>> patch as it stand have no effect there i.e. no change ? >>>>> arm-linux-gnueabihf usually means to me someone has configured with >>>>> --with-float=hard, so there are no regressions in the hard float ABI >>>>> case, >>>>> >>>> >>>> I know it proves little. When I say arm-linux-gnueabihf >>>> I do in fact mean --enable-languages=all,ada,go,obj-c++ >>>> --with-arch=armv7-a --with-tune=cortex-a9 --with-fpu=vfpv3-d16 >>>> --with-float=hard. >>>> >>>> My main interest in the stack usage is of course not because of linux, >>>> but because of eCos where we have very small task stacks and in fact >>>> no fpu support by the O/S at all, so that patch is exactly what we >>>> need. >>>> >>>> >>>> Bootstrapped and reg-tested on arm-linux-gnueabihf >>>> Is it OK for trunk? >>>> >>>> >>>> Thanks >>>> Bernd.
