On Tue, Jul 21, 2026 at 6:44 AM H.J. Lu <[email protected]> wrote: > > With the silicon vendor guarantees from Intel, AMD, Hygon and Zhaoxin in: > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104688 > > many software developers would happily use inline 128-bit atomic loads > and stores in their programs because they only target compatible CPUs. > Add -m128bit-atomic to generate 128-bit atomic loads and stores to avoid > the overhead of calling into libatomic. Enable -m128bit-atomic by default > if supported by the targeting processor, which is one of x86-64-v3 capable > processors as well as AVX capable processors from Intel, AMD, Hygon and > Zhaoxin, with SEE2 and CMPXCHG16B enabled.
There are some typos, SEE2 should be SSE2. Fixed in my local copy. > gcc/ > > PR target/94649 > PR target/126293 > * common/config/i386/i386-cpuinfo.h (ix86_decode_cpu_info): New > function. > * config/i386/i386-options.cc (ix86_function_specific_save): Save > x_ix86_128bit_atomic. > (ix86_function_specific_restore): Restore x_ix86_128bit_atomic. > (ix86_option_override_internal): Turn off -m128bit-atomic when > CMPXCHG16B is disabled and turn on CMPXCHG16B when -m128bit-atomic > is enabled. Enable -m128bit-atomic by default if supported by > the targeting processor with SEE2 and CMPXCHG16B enabled. > * config/i386/i386.opt (x_ix86_128bit_atomic): New TargetSave. > (m128bit-atomic): New option. > * config/i386/i386.opt.urls: Regenerated. > * config/i386/sync.md (atomic_loadti): New pattern. > (atomic_loadti_sse): Likewise. > (atomic_storeti): Likewise. > (atomic_storeti_sse): Likewise. > * doc/invoke.texi: Document -m128bit-atomic. > > gcc/testsuite/ > > PR target/94649 > PR target/126293 > * g++.target/i386/pr94649-1.C: New test. > * gcc.target/i386/pr126293-1a.c: Likewise. > * gcc.target/i386/pr126293-1b.c: Likewise. > * gcc.target/i386/pr126293-1c.c: Likewise. > * gcc.target/i386/pr126293-2a.c: Likewise. > * gcc.target/i386/pr126293-2b.c: Likewise. > * gcc.target/i386/pr126293-3a.c: Likewise. > * gcc.target/i386/pr126293-3b.c: Likewise. > * gcc.target/i386/pr126293-4a.c: Likewise. > * gcc.target/i386/pr126293-4b.c: Likewise. > * gcc.target/i386/pr126293-4c.c: Likewise. > * gcc.target/i386/pr126293-4d.c: Likewise. > * gcc.target/i386/pr126293-4e.c: Likewise. > * gcc.target/i386/pr126293-4f.c: Likewise. > * gcc.target/i386/pr126293-4g.c: Likewise. > * gcc.target/i386/pr126293-4h.c: Likewise. > * gcc.target/i386/pr126293-4i.c: Likewise. > * gcc.target/i386/pr126293-4j.c: Likewise. > * gcc.target/i386/pr126293-4k.c: Likewise. > * gcc.target/i386/pr126293-4l.c: Likewise. > * gcc.target/i386/pr126293-4m.c: Likewise. > * gcc.target/i386/pr126293-4n.c: Likewise. > * gcc.target/i386/pr126293-4o.c: Likewise. > * gcc.target/i386/pr126293-4p.c: Likewise. > * gcc.target/i386/pr126293-4q.c: Likewise. > * gcc.target/i386/pr126293-5.c: Likewise. > * gcc.target/i386/pr126293-6.c: Likewise. > * gcc.target/i386/pr126293-7.c: Likewise. > * gcc.target/i386/pr126293-8.c: Likewise. > * gcc.target/i386/pr126293-9.c: Likewise. > * gcc.target/i386/pr126293-10.c: Likewise. > * gcc.target/i386/pr126293-11.c: Likewise. > * gcc.target/i386/pr126293-12.c: Likewise. > * gcc.target/i386/pr126293-13.c: Likewise. > * gcc.target/i386/pr126293-14.c: Likewise. > * gcc.target/i386/pr126293-15.c: Likewise. > > > -- > H.J. -- H.J.
