>-----Original Message----- >From: Matt Turner [mailto:[email protected]] >Sent: Monday, March 9, 2020 9:00 AM >To: Shiyou Yin >Cc: pixman >Subject: Re: [Pixman] [PATCH v2] build: improve control logic for enabling MMI. > >Thank you for the patch! > >On Fri, Mar 6, 2020 at 3:28 AM Shiyou Yin <[email protected]> wrote: >> >> From: Yin Shiyou <yinshiyou-hf@loongson> > >Should be yinshiyou-hf@loongson*.cn*?
Yes, will update. >> >> 1. Replace LS_CFLAGS with MMI_CFLAGS to express its intention more >> accurately. >> LS_CFLAGS is still available, but it is not recommended. > >I'm not aware of any reasons why LS_CFLAGS needs to stay for >compatibility. Do we know of any distros that set it to override the >-march=... value? No, keep LS_CFLAGS is just considering that users may be used to it. > >> 2. Improve the control logic for enabling MMI. >> >> Three essential conditions for enabling MMI: >> 1) user have not specify --disable-loongson-mmi. >> 2) MMI options has been specified by MMI_CFLAGS,CC or compiler's default >> setting. >> 3) compiler supports these MMI options. >> --- >> configure.ac | 69 >> ++++++++++++++++++++++++++++++++++++++++-------------------- > >We should also update meson.build. I expect/hope that the autotools >build system will go away sometime in the future. Will update. > >I'm not sure I entirely understand the patch. I understand that the >objective is to make it possible to easily build pixman for Loongson3A >and use the pixman-mmx.c optimizations. It's my original goal. In my first patch, I replaced '-march=loongson2f' with -mloongson-mmi directly. But it raised objections, Yunqiang said it will cause break on 2F for the different opcode on 2F and 3A. I tried to find a 2F to verify this, but I havn't found yet. >I think it's currently possible to build pixman on mips without >specifying -march=loongson* in CFLAGS and it will enable the >pixman-mmx.c paths and choose them at runtime. Is part of the goal to >keep that working? If so, could we just use the -mloongson-mmi flag to >compile pixman-mmx.c? Yes, from last year, compiler has add '-mloongson-mmi' to support MMI, It's not recommended to use -march=* to build MMI any more. What we worry about is -march=loongson2f and -mloongson-mmi will generate different opcode.(This is not verified yet.) >Or does that flag mean the Loongson3A variants of the instructions? >What happens if you compile with -march=loongson2f -mloongson-mmi? >Does GCC generate instructions compatible with 2F or 3A? I am still trying to find out a 2F to verify this. If -mloongson-mmi works well on 2F, maybe we can revert to the first version of my patch. If -mloongson-mmi caused break of 2F, then this patch may be a suitable option. _______________________________________________ Pixman mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/pixman
