> On Jan 30, 2017, at 3:23 PM, Kyrill Tkachov <kyrylo.tkac...@foss.arm.com> > wrote: > > Hi Maxim, > > On 30/01/17 12:06, Maxim Kuvyrkov wrote: >> This patch enables prefetching at -O3 for aarch64 cores that set >> "simultaneous prefetches" parameter above 0. There are currently no such >> settings, so this patch doesn't change default code generation. >> >> I'm now working on improvements to -fprefetch-loop-arrays pass to make it >> suitable for -O2. I'll post this work in the next month. >> >> Bootstrapped and regtested on x86_64-linux-gnu and aarch64-linux-gnu. >> > > Are you aiming to get this in for GCC 8? > I have one small comment on this patch: > > + /* Enable sw prefetching at -O3 for CPUS that have prefetch, and we > + have deemed it beneficial (signified by setting > + prefetch.num_slots to 1 or more). */ > + if (flag_prefetch_loop_arrays < 0 > + && HAVE_prefetch > > HAVE_prefetch will always be true on aarch64. > I imagine midend code that had logic like this would need this check, but > aarch64-specific code shouldn't need it.
Agree, I'll remove HAVE_prefetch. This pattern was copied from other backends, and HAVE_prefetch is most likely a historical artifact. -- Maxim Kuvyrkov www.linaro.org
