On Tue, 3 Dec 2019 at 14:45, Wilco Dijkstra <wilco.dijks...@arm.com> wrote: > > Hi, > > Part 2, split off from > https://gcc.gnu.org/ml/gcc-patches/2019-11/msg00399.html > > To enable cores to use the correct max_cond_insns setting, use the > core-specific > tuning when a CPU/tune is selected unless -mrestrict-it is explicitly set. >
Hi, This patch (r278968) is causing regressions when building GCC --target arm-none-linux-gnueabihf --with-mode thumb --with-cpu cortex-a57 --with-fpu crypto-neon-fp-armv8 because the assembler (gas version 2.33.1) complains: /ccc7z5eW.s:4267: IT blocks containing more than one conditional instruction are performance deprecated in ARMv8-A and ARMv8-R I guess that's related to what you say about -mrestrict-it ? Christophe > On Cortex-A57 this gives 1.1% performance gain on SPECINT2006 as well as a > 0.4% codesize reduction. > > Bootstrapped on armhf. OK for commit? > > ChangeLog: > > 2019-12-03 Wilco Dijkstra <wdijk...@arm.com> > > * config/arm/arm.c (arm_option_override_internal): > Use max_cond_insns from CPU tuning unless -mrestrict-it is used. > -- > > diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c > index > daebe76352d62ad94556762b4e3bc3d0532ad411..5ed9046988996e56f754c5588e4d25d5ecdd6b03 > 100644 > --- a/gcc/config/arm/arm.c > +++ b/gcc/config/arm/arm.c > @@ -3041,6 +3041,11 @@ arm_option_override_internal (struct gcc_options *opts, > if (!TARGET_THUMB2_P (opts->x_target_flags) || !arm_arch_notm) > opts->x_arm_restrict_it = 0; > > + /* Use the IT size from CPU specific tuning unless -mrestrict-it is used. > */ > + if (!opts_set->x_arm_restrict_it > + && (opts_set->x_arm_cpu_string || opts_set->x_arm_tune_string)) > + opts->x_arm_restrict_it = 0; > + > /* Enable -munaligned-access by default for > - all ARMv6 architecture-based processors when compiling for a 32-bit > ISA > i.e. Thumb2 and ARM state only.
