Re: [AArch64] PR105162: emit barrier for __sync and __atomic builtins on CPUs without LSE

"Pop, Sebastian" writes: > Please see attached the patch back-ported to branches 12, 11, 10, and 9. > Tested on aarch64-linux with bootstrap and regression test. > Ok to commit to the GCC active branches? OK, thanks. Only very safe patches are supposed to be going into GCC 9 at this stage, and

Re: [AArch64] PR105162: emit barrier for __sync and __atomic builtins on CPUs without LSE

Please see attached the patch back-ported to branches 12, 11, 10, and 9. Tested on aarch64-linux with bootstrap and regression test. Ok to commit to the GCC active branches? Thanks, SebastianFrom bba8d09284f3478f7d542ca4e7812d4c55e25bd4 Mon Sep 17 00:00:00 2001 From: Sebastian Pop Date: Mon, 18

Re: [AArch64] PR105162: emit barrier for __sync and __atomic builtins on CPUs without LSE

Hi Sebastian, >> Note the patch still needs an appropriate commit message. > > Added the following ChangeLog entry to the commit message. > > * config/aarch64/aarch64-protos.h (atomic_ool_names): Increase >dimension > of str array. > * config/aarch64/aarch64.cc

Re: [AArch64] PR105162: emit barrier for __sync and __atomic builtins on CPUs without LSE

"Pop, Sebastian via Gcc-patches" writes: >> Yes this looks good to me (still needs maintainer approval). > > Thanks again Wilco for your review. > >> One minor nitpick, >> a few of the tests check for __aarch64_cas2 - this should be >> __aarch64_cas2_sync. > > Fixed in the attached patch. > >>

Re: [AArch64] PR105162: emit barrier for __sync and __atomic builtins on CPUs without LSE

> Yes this looks good to me (still needs maintainer approval). Thanks again Wilco for your review. > One minor nitpick, > a few of the tests check for __aarch64_cas2 - this should be > __aarch64_cas2_sync. Fixed in the attached patch. > Note the patch still needs an appropriate commit

Re: [AArch64] PR105162: emit barrier for __sync and __atomic builtins on CPUs without LSE

Hi Sebastian, > Please find attached the patch amended following your recommendations. > The number of new functions for _sync is reduced by 3x. > I tested the patch on Graviton2 aarch64-linux. > I also checked by hand that the outline functions in libgcc look similar to > what GCC produces for

Re: [AArch64] PR105162: emit barrier for __sync and __atomic builtins on CPUs without LSE

Hi Wilco, Thanks for your review. Please find attached the patch amended following your recommendations. The number of new functions for _sync is reduced by 3x. I tested the patch on Graviton2 aarch64-linux. I also checked by hand that the outline functions in libgcc look similar to what GCC

Re: [AArch64] PR105162: emit barrier for __sync and __atomic builtins on CPUs without LSE

Hi Sebastian, > Wilco pointed out in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105162#c7​ > that > "Only __sync needs the extra full barrier, but __atomic does not." > The attached patch does that by adding out-of-line functions for > MEMMODEL_SYNC_*. > Those new functions contain a barrier

Re: [AArch64] PR105162: emit barrier for __sync and __atomic builtins on CPUs without LSE

Hi, Wilco pointed out in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105162#c7? that "Only __sync needs the extra full barrier, but __atomic does not." The attached patch does that by adding out-of-line functions for MEMMODEL_SYNC_*. Those new functions contain a barrier on the path

[AArch64] PR105162: emit barrier for __sync and __atomic builtins on CPUs without LSE

Hi, With -moutline-atomics gcc stops generating a barrier for __sync builtins: https://gcc.gnu.org/PR105162 This is a problem on CPUs without LSE instructions where the ld/st exclusives do not guarantee a full barrier. The attached patch