RE: [PATCH] i386: Only enable small loop unrolling in backend [PR 107602]
> -Original Message- > From: Wang, Hongyu > Sent: Saturday, November 19, 2022 2:26 PM > To: gcc-patches@gcc.gnu.org > Cc: richard.guent...@gmail.com; ubiz...@gmail.com; Liu, Hongtao > > Subject: [PATCH] i386: Only enable small loop unrolling in backend [PR 107602] > > Hi, > > Followed by the discussion in pr107602, -munroll-only-small-loops Does not PR107692? > turns on/off -funroll-loops, and current check in pass_rtl_unroll_loops::gate > would cause -funroll-loops do not take effect. Revert the change about > targetm.loop_unroll_adjust and apply the backend option change to strictly > follow the rule that -funroll-loops takes full control of loop unrolling, and > munroll-only-small-loops just change its behavior to unroll small size loops. > > Bootstrapped and regtested on x86-64-pc-linux-gnu. > > Ok for trunk? > > gcc/ChangeLog: > > PR target/107602 > * common/config/i386/i386-common.cc (ix86_optimization_table): > Enable loop unroll O2, disable -fweb and -frename-registers > by default. > * config/i386/i386-options.cc > (ix86_override_options_after_change): > Disable small loop unroll when funroll-loops enabled, reset > cunroll_grow_size when it is not explicitly enabled. > (ix86_option_override_internal): Call > ix86_override_options_after_change instead of calling > ix86_recompute_optlev_based_flags and ix86_default_align > separately. > * config/i386/i386.cc (ix86_loop_unroll_adjust): Adjust unroll > factor if -munroll-only-small-loops enabled. > * loop-init.cc (pass_rtl_unroll_loops::gate): Do not enable > loop unrolling for -O2-speed. > (pass_rtl_unroll_loops::execute): Rmove > targetm.loop_unroll_adjust check. > > gcc/testsuite/ChangeLog: > > PR target/107602 > * gcc.target/i386/pr86270.c: Add -fno-unroll-loops. > * gcc.target/i386/pr93002.c: Likewise. > --- > gcc/common/config/i386/i386-common.cc | 8 ++ > gcc/config/i386/i386-options.cc | 34 ++--- > gcc/config/i386/i386.cc | 18 - > gcc/loop-init.cc| 11 +++- > gcc/testsuite/gcc.target/i386/pr86270.c | 2 +- > gcc/testsuite/gcc.target/i386/pr93002.c | 2 +- > 6 files changed, 49 insertions(+), 26 deletions(-) > > diff --git a/gcc/common/config/i386/i386-common.cc > b/gcc/common/config/i386/i386-common.cc > index 6ce2a588adc..660a977b68b 100644 > --- a/gcc/common/config/i386/i386-common.cc > +++ b/gcc/common/config/i386/i386-common.cc > @@ -1808,7 +1808,15 @@ static const struct default_options > ix86_option_optimization_table[] = > /* The STC algorithm produces the smallest code at -Os, for x86. */ > { OPT_LEVELS_2_PLUS, OPT_freorder_blocks_algorithm_, NULL, >REORDER_BLOCKS_ALGORITHM_STC }, > + > +/* Turn on -funroll-loops with -munroll-only-small-loops to enable small > + loop unrolling at -O2. */ > +{ OPT_LEVELS_2_PLUS_SPEED_ONLY, OPT_funroll_loops, NULL, 1 }, > { OPT_LEVELS_2_PLUS_SPEED_ONLY, OPT_munroll_only_small_loops, NULL, > 1 }, > +/* Turns off -frename-registers and -fweb which are enabled by > + funroll-loops. */ > +{ OPT_LEVELS_ALL, OPT_frename_registers, NULL, 0 }, > +{ OPT_LEVELS_ALL, OPT_fweb, NULL, 0 }, > /* Turn off -fschedule-insns by default. It tends to make the > problem with not enough registers even worse. */ > { OPT_LEVELS_ALL, OPT_fschedule_insns, NULL, 0 }, diff --git > a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc index > e5c77f3a84d..bc1d36e36a8 100644 > --- a/gcc/config/i386/i386-options.cc > +++ b/gcc/config/i386/i386-options.cc > @@ -1838,8 +1838,37 @@ ix86_recompute_optlev_based_flags (struct > gcc_options *opts, void ix86_override_options_after_change (void) { > + /* Default align_* from the processor table. */ >ix86_default_align (&global_options); > + >ix86_recompute_optlev_based_flags (&global_options, &global_options_set); > + > + /* Disable unrolling small loops when there's explicit > + -f{,no}unroll-loop. */ > + if ((OPTION_SET_P (flag_unroll_loops)) > + || (OPTION_SET_P (flag_unroll_all_loops) > + && flag_unroll_all_loops)) > +{ > + if (!OPTION_SET_P (ix86_unroll_only_small_loops)) > + ix86_unroll_only_small_loops = 0; > + /* Re-enable -frename-registers and -fweb if funroll-loops > + enabled. */ > + if (!OPTION_SET_P (flag_web)) > + flag_web = flag_unroll_loops; > + if (!OPTION_SET_P (flag_rename_registers)) > + flag_rename_registers = flag_unroll_loops; > + /* -fcunroll-grow-size default follws -f[no]-unroll-loops. */ > + if (!OPTION_SET_P (flag_cunroll_grow_size)) > + flag_cunroll_grow_size = flag_unroll_loops > + || flag_peel_loops > + || optimize >= 3; > +} > + else > +{ > + if (!OPTION_SET_P (flag_cunroll_gr
Re: [PATCH] i386: Only enable small loop unrolling in backend [PR 107602]
On Mon, Nov 21, 2022 at 9:01 AM Liu, Hongtao via Gcc-patches wrote: > > > > > -Original Message- > > From: Wang, Hongyu > > Sent: Saturday, November 19, 2022 2:26 PM > > To: gcc-patches@gcc.gnu.org > > Cc: richard.guent...@gmail.com; ubiz...@gmail.com; Liu, Hongtao > > > > Subject: [PATCH] i386: Only enable small loop unrolling in backend [PR > > 107602] > > > > Hi, > > > > Followed by the discussion in pr107602, -munroll-only-small-loops Does not > PR107692? > > turns on/off -funroll-loops, and current check in > > pass_rtl_unroll_loops::gate > > would cause -funroll-loops do not take effect. Revert the change about It's not necessarily right. unroll_factor will be set as 1 when -fno-unroll-loops, which is exactly -fno-unroll-loops means. > > targetm.loop_unroll_adjust and apply the backend option change to strictly > > follow the rule that -funroll-loops takes full control of loop unrolling, > > and > > munroll-only-small-loops just change its behavior to unroll small size > > loops. > > > > Bootstrapped and regtested on x86-64-pc-linux-gnu. > > > > Ok for trunk? > > > > gcc/ChangeLog: > > > > PR target/107602 > > * common/config/i386/i386-common.cc (ix86_optimization_table): > > Enable loop unroll O2, disable -fweb and -frename-registers > > by default. > > * config/i386/i386-options.cc > > (ix86_override_options_after_change): > > Disable small loop unroll when funroll-loops enabled, reset > > cunroll_grow_size when it is not explicitly enabled. > > (ix86_option_override_internal): Call > > ix86_override_options_after_change instead of calling > > ix86_recompute_optlev_based_flags and ix86_default_align > > separately. > > * config/i386/i386.cc (ix86_loop_unroll_adjust): Adjust unroll > > factor if -munroll-only-small-loops enabled. > > * loop-init.cc (pass_rtl_unroll_loops::gate): Do not enable > > loop unrolling for -O2-speed. > > (pass_rtl_unroll_loops::execute): Rmove > > targetm.loop_unroll_adjust check. > > > > gcc/testsuite/ChangeLog: > > > > PR target/107602 > > * gcc.target/i386/pr86270.c: Add -fno-unroll-loops. > > * gcc.target/i386/pr93002.c: Likewise. > > --- > > gcc/common/config/i386/i386-common.cc | 8 ++ > > gcc/config/i386/i386-options.cc | 34 ++--- > > gcc/config/i386/i386.cc | 18 - > > gcc/loop-init.cc| 11 +++- > > gcc/testsuite/gcc.target/i386/pr86270.c | 2 +- > > gcc/testsuite/gcc.target/i386/pr93002.c | 2 +- > > 6 files changed, 49 insertions(+), 26 deletions(-) > > > > diff --git a/gcc/common/config/i386/i386-common.cc > > b/gcc/common/config/i386/i386-common.cc > > index 6ce2a588adc..660a977b68b 100644 > > --- a/gcc/common/config/i386/i386-common.cc > > +++ b/gcc/common/config/i386/i386-common.cc > > @@ -1808,7 +1808,15 @@ static const struct default_options > > ix86_option_optimization_table[] = > > /* The STC algorithm produces the smallest code at -Os, for x86. */ > > { OPT_LEVELS_2_PLUS, OPT_freorder_blocks_algorithm_, NULL, > >REORDER_BLOCKS_ALGORITHM_STC }, > > + > > +/* Turn on -funroll-loops with -munroll-only-small-loops to enable > > small > > + loop unrolling at -O2. */ > > +{ OPT_LEVELS_2_PLUS_SPEED_ONLY, OPT_funroll_loops, NULL, 1 }, > > { OPT_LEVELS_2_PLUS_SPEED_ONLY, OPT_munroll_only_small_loops, NULL, > > 1 }, > > +/* Turns off -frename-registers and -fweb which are enabled by > > + funroll-loops. */ > > +{ OPT_LEVELS_ALL, OPT_frename_registers, NULL, 0 }, > > +{ OPT_LEVELS_ALL, OPT_fweb, NULL, 0 }, > > /* Turn off -fschedule-insns by default. It tends to make the > > problem with not enough registers even worse. */ > > { OPT_LEVELS_ALL, OPT_fschedule_insns, NULL, 0 }, diff --git > > a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc index > > e5c77f3a84d..bc1d36e36a8 100644 > > --- a/gcc/config/i386/i386-options.cc > > +++ b/gcc/config/i386/i386-options.cc > > @@ -1838,8 +1838,37 @@ ix86_recompute_optlev_based_flags (struct > > gcc_options *opts, void ix86_override_options_after_change (void) { > > + /* Default align_* from the processor table. */ > >ix86_default_align (&global_options); > > + > >ix86_recompute_optlev_based_flags (&global_options, &global_options_set); > > + > > + /* Disable unrolling small loops when there's explicit > > + -f{,no}unroll-loop. */ > > + if ((OPTION_SET_P (flag_unroll_loops)) > > + || (OPTION_SET_P (flag_unroll_all_loops) > > + && flag_unroll_all_loops)) > > +{ > > + if (!OPTION_SET_P (ix86_unroll_only_small_loops)) > > + ix86_unroll_only_small_loops = 0; > > + /* Re-enable -frename-registers and -fweb if funroll-loops > > + enabled. */ > > + if (!OPTION_SET_P (flag_web)) > > + flag_web = flag_unroll_loops; > > + if (!OPTION_SET_P (flag
Re: [PATCH] i386: Only enable small loop unrolling in backend [PR 107602]
> It's not necessarily right. unroll_factor will be set as 1 when > -fno-unroll-loops, which is exactly -fno-unroll-loops means. Not that exactly, -fno-unroll-loops previously will prevent the pass from running, and on the current trunk the pass still runs. Actually I think the implementation on trunk is a bit tricky since we use a target hook without return value to execute the pass. Also the logic !OPTION_SET_P looks quite like a workaround. IMHO this is also not good for maintenance. Hongtao Liu via Gcc-patches 于2022年11月21日周一 09:33写道: > > On Mon, Nov 21, 2022 at 9:01 AM Liu, Hongtao via Gcc-patches > wrote: > > > > > > > > > -Original Message- > > > From: Wang, Hongyu > > > Sent: Saturday, November 19, 2022 2:26 PM > > > To: gcc-patches@gcc.gnu.org > > > Cc: richard.guent...@gmail.com; ubiz...@gmail.com; Liu, Hongtao > > > > > > Subject: [PATCH] i386: Only enable small loop unrolling in backend [PR > > > 107602] > > > > > > Hi, > > > > > > Followed by the discussion in pr107602, -munroll-only-small-loops Does not > > PR107692? > > > turns on/off -funroll-loops, and current check in > > > pass_rtl_unroll_loops::gate > > > would cause -funroll-loops do not take effect. Revert the change about > It's not necessarily right. unroll_factor will be set as 1 when > -fno-unroll-loops, which is exactly -fno-unroll-loops means. > > > targetm.loop_unroll_adjust and apply the backend option change to strictly > > > follow the rule that -funroll-loops takes full control of loop unrolling, > > > and > > > munroll-only-small-loops just change its behavior to unroll small size > > > loops. > > > > > > Bootstrapped and regtested on x86-64-pc-linux-gnu. > > > > > > Ok for trunk? > > > > > > gcc/ChangeLog: > > > > > > PR target/107602 > > > * common/config/i386/i386-common.cc (ix86_optimization_table): > > > Enable loop unroll O2, disable -fweb and -frename-registers > > > by default. > > > * config/i386/i386-options.cc > > > (ix86_override_options_after_change): > > > Disable small loop unroll when funroll-loops enabled, reset > > > cunroll_grow_size when it is not explicitly enabled. > > > (ix86_option_override_internal): Call > > > ix86_override_options_after_change instead of calling > > > ix86_recompute_optlev_based_flags and ix86_default_align > > > separately. > > > * config/i386/i386.cc (ix86_loop_unroll_adjust): Adjust unroll > > > factor if -munroll-only-small-loops enabled. > > > * loop-init.cc (pass_rtl_unroll_loops::gate): Do not enable > > > loop unrolling for -O2-speed. > > > (pass_rtl_unroll_loops::execute): Rmove > > > targetm.loop_unroll_adjust check. > > > > > > gcc/testsuite/ChangeLog: > > > > > > PR target/107602 > > > * gcc.target/i386/pr86270.c: Add -fno-unroll-loops. > > > * gcc.target/i386/pr93002.c: Likewise. > > > --- > > > gcc/common/config/i386/i386-common.cc | 8 ++ > > > gcc/config/i386/i386-options.cc | 34 ++--- > > > gcc/config/i386/i386.cc | 18 - > > > gcc/loop-init.cc| 11 +++- > > > gcc/testsuite/gcc.target/i386/pr86270.c | 2 +- > > > gcc/testsuite/gcc.target/i386/pr93002.c | 2 +- > > > 6 files changed, 49 insertions(+), 26 deletions(-) > > > > > > diff --git a/gcc/common/config/i386/i386-common.cc > > > b/gcc/common/config/i386/i386-common.cc > > > index 6ce2a588adc..660a977b68b 100644 > > > --- a/gcc/common/config/i386/i386-common.cc > > > +++ b/gcc/common/config/i386/i386-common.cc > > > @@ -1808,7 +1808,15 @@ static const struct default_options > > > ix86_option_optimization_table[] = > > > /* The STC algorithm produces the smallest code at -Os, for x86. */ > > > { OPT_LEVELS_2_PLUS, OPT_freorder_blocks_algorithm_, NULL, > > >REORDER_BLOCKS_ALGORITHM_STC }, > > > + > > > +/* Turn on -funroll-loops with -munroll-only-small-loops to enable > > > small > > > + loop unrolling at -O2. */ > > > +{ OPT_LEVELS_2_PLUS_SPEED_ONLY, OPT_funroll_loops, NULL, 1 }, > > > { OPT_LEVELS_2_PLUS_SPEED_ONLY, OPT_munroll_only_small_loops, NULL, > > > 1 }, > > > +/* Turns off -frename-registers and -fweb which are enabled by > > > + funroll-loops. */ > > > +{ OPT_LEVELS_ALL, OPT_frename_registers, NULL, 0 }, > > > +{ OPT_LEVELS_ALL, OPT_fweb, NULL, 0 }, > > > /* Turn off -fschedule-insns by default. It tends to make the > > > problem with not enough registers even worse. */ > > > { OPT_LEVELS_ALL, OPT_fschedule_insns, NULL, 0 }, diff --git > > > a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc index > > > e5c77f3a84d..bc1d36e36a8 100644 > > > --- a/gcc/config/i386/i386-options.cc > > > +++ b/gcc/config/i386/i386-options.cc > > > @@ -1838,8 +1838,37 @@ ix86_recompute_optlev_based_flags (struct > > > gcc_options *opts, void ix86_override_options_after_change (void) { > > >
Re: [PATCH] i386: Only enable small loop unrolling in backend [PR 107602]
On 11/18/22 23:25, Hongyu Wang via Gcc-patches wrote: Hi, Followed by the discussion in pr107602, -munroll-only-small-loops Does not turns on/off -funroll-loops, and current check in pass_rtl_unroll_loops::gate would cause -funroll-loops do not take effect. Revert the change about targetm.loop_unroll_adjust and apply the backend option change to strictly follow the rule that -funroll-loops takes full control of loop unrolling, and munroll-only-small-loops just change its behavior to unroll small size loops. Bootstrapped and regtested on x86-64-pc-linux-gnu. Ok for trunk? gcc/ChangeLog: PR target/107602 * common/config/i386/i386-common.cc (ix86_optimization_table): Enable loop unroll O2, disable -fweb and -frename-registers by default. * config/i386/i386-options.cc (ix86_override_options_after_change): Disable small loop unroll when funroll-loops enabled, reset cunroll_grow_size when it is not explicitly enabled. (ix86_option_override_internal): Call ix86_override_options_after_change instead of calling ix86_recompute_optlev_based_flags and ix86_default_align separately. * config/i386/i386.cc (ix86_loop_unroll_adjust): Adjust unroll factor if -munroll-only-small-loops enabled. * loop-init.cc (pass_rtl_unroll_loops::gate): Do not enable loop unrolling for -O2-speed. (pass_rtl_unroll_loops::execute): Rmove targetm.loop_unroll_adjust check. The reversion of the loop-init.cc changes is fine. The x86 maintainers will need to chime in on the rest. Consider installing the loop-init.cc reversion immediately as the current state has regressed s390 and potentially other targets. jeff
Re: [PATCH] i386: Only enable small loop unrolling in backend [PR 107602]
On Tue, Nov 22, 2022 at 1:41 AM Jeff Law via Gcc-patches wrote: > > > On 11/18/22 23:25, Hongyu Wang via Gcc-patches wrote: > > Hi, > > > > Followed by the discussion in pr107602, -munroll-only-small-loops > > Does not turns on/off -funroll-loops, and current check in > > pass_rtl_unroll_loops::gate would cause -funroll-loops do not take > > effect. Revert the change about targetm.loop_unroll_adjust and apply > > the backend option change to strictly follow the rule that > > -funroll-loops takes full control of loop unrolling, and > > munroll-only-small-loops just change its behavior to unroll small size > > loops. > > > > Bootstrapped and regtested on x86-64-pc-linux-gnu. > > > > Ok for trunk? > > > > gcc/ChangeLog: > > > > PR target/107602 > > * common/config/i386/i386-common.cc (ix86_optimization_table): > > Enable loop unroll O2, disable -fweb and -frename-registers > > by default. > > * config/i386/i386-options.cc > > (ix86_override_options_after_change): > > Disable small loop unroll when funroll-loops enabled, reset > > cunroll_grow_size when it is not explicitly enabled. > > (ix86_option_override_internal): Call > > ix86_override_options_after_change instead of calling > > ix86_recompute_optlev_based_flags and ix86_default_align > > separately. > > * config/i386/i386.cc (ix86_loop_unroll_adjust): Adjust unroll > > factor if -munroll-only-small-loops enabled. > > * loop-init.cc (pass_rtl_unroll_loops::gate): Do not enable > > loop unrolling for -O2-speed. > > (pass_rtl_unroll_loops::execute): Rmove > > targetm.loop_unroll_adjust check. > The reversion of the loop-init.cc changes is fine. The x86 maintainers > will need to chime in on the rest. Consider installing the loop-init.cc > reversion immediately as the current state has regressed s390 and > potentially other targets. x86 part is ok. > > > jeff > -- BR, Hongtao
Re: [PATCH] i386: Only enable small loop unrolling in backend [PR 107602]
Hi Jeff, > The reversion of the loop-init.cc changes is fine. The x86 maintainers > will need to chime in on the rest. Consider installing the loop-init.cc > reversion immediately as the current state has regressed s390 and > potentially other targets. I've posted a patch in https://gcc.gnu.org/pipermail/gcc-patches/2022-November/606478.html to change the rs6000 target and there is a discussion ongoing. If we draw a conclusion that we only want to make changes in the backend, I will install this one. -- Regards, Hongyu, Wang