On 7/6/21 3:57 AM, Richard Biener wrote:
On Mon, 5 Jul 2021, Richard Biener wrote:On Fri, 2 Jul 2021, Martin Sebor wrote:On 7/2/21 5:55 AM, Richard Biener wrote:This adds the -fmove-loop-stores option, mainly as a way to disable the store-motion part of GIMPLE invariant motion (-ftree-loop-im) which is enabled by default. It might be sensible to turn off -fmove-loop-stores at -O1 since it can result in compile-time as well as memory usage issues but this patch tries to preserve existing behavior besides introducing the new option with the exception of -Og where I've disabled it. Controlling store-motion has been made easy by earlier refactoring for the invariant motion only use after loop interchange. Bootstrap and regtest running on x86_64-unknown-linux-gnu. OK? Thanks, Richard. 2021-07-02 Richard Biener <rguent...@suse.de> * doc/invoke.texi (fmove-loop-stores): Document. * common.opt (fmove-loop-stores): New option. * opts.c (default_options_table): Enable -fmove-loop-stores at -O1 but not -Og. * tree-ssa-loop-im.c (pass_lim::execute): Pass flag_move_loop_stores instead of true to loop_invariant_motion_in_fun. --- gcc/common.opt | 4 ++++ gcc/doc/invoke.texi | 11 +++++++++-- gcc/opts.c | 1 + gcc/tree-ssa-loop-im.c | 2 +- 4 files changed, 15 insertions(+), 3 deletions(-) diff --git a/gcc/common.opt b/gcc/common.opt index 5b03bbc6662..d9da1131eda 100644 --- a/gcc/common.opt +++ b/gcc/common.opt @@ -2084,6 +2084,10 @@ fmove-loop-invariants Common Var(flag_move_loop_invariants) Optimization Move loop invariant computations out of loops.+fmove-loop-stores+Common Var(flag_move_loop_stores) Optimization +Move stores out of loops. + fdce Common Var(flag_dce) Init(1) Optimization Use the RTL dead code elimination pass. diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index a9fd5fdc104..7b4f5d26738 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -528,7 +528,7 @@ Objective-C and Objective-C++ Dialects}. -floop-parallelize-all -flra-remat -flto -flto-compression-level @gol -flto-partition=@var{alg} -fmerge-all-constants @gol -fmerge-constants -fmodulo-sched -fmodulo-sched-allow-regmoves @gol --fmove-loop-invariants -fno-branch-count-reg @gol +-fmove-loop-invariants -fmove-loop-stores -fno-branch-count-reg @gol -fno-defer-pop -fno-fp-int-builtin-inexact -fno-function-cse @gol -fno-guess-branch-probability -fno-inline -fno-math-errno -fno-peephole @gol -fno-peephole2 -fno-printf-return-value -fno-sched-interblock @gol @@ -10260,6 +10260,7 @@ compilation time. -fipa-reference-addressable @gol -fmerge-constants @gol -fmove-loop-invariants @gol +-fmove-loop-stores@gol -fomit-frame-pointer @gol -freorder-blocks @gol -fshrink-wrap @gol @@ -10403,7 +10404,7 @@ optimization flags except for those that may interfere with debugging: @gccoptlist{-fbranch-count-reg -fdelayed-branch @gol -fdse -fif-conversion -fif-conversion2 @gol -finline-functions-called-once @gol --fmove-loop-invariants -fssa-phiopt @gol +-fmove-loop-invariants -fmove-loop-stores -fssa-phiopt @gol -ftree-bit-ccp -ftree-dse -ftree-pta -ftree-sra}@end table@@ -13011,6 +13012,12 @@ Enabled by @option{-O3}, @option{-fprofile-use}, and @option{-fauto-profile}. Enables the loop invariant motion pass in the RTL loop optimizer. Enabled at level @option{-O1} and higher, except for @option{-Og}.+@item -fmove-loop-stores+@opindex fmove-loop-stores +Enables the loop store motion pass in the GIMPLE loop optimizer. Note for +this option to have an effect @code{-ftree-loop-im} has to be enabled as well.^^^^^ The @code markup should be @option as well (same as below).Ah, thanks - fixed.I find the brief text added to gcc/common.opt more informative than this longer description. Explaining what the store motion pass does in a few words would be helpful to those not familiar with the implementation.OK, so is the following more useful then? " @item -fmove-loop-stores @opindex fmove-loop-stores Enables the loop store motion pass in the GIMPLE loop optimizer. This moves invariant stores to after the end of the loop in exchange for carrying the stored value in a register across the iteration. Note for this option to have an effect @option{-ftree-loop-im} has to be enabled as well. Enabled at level @option{-O1} and higher, except for @option{-Og}. "I've now pushed with this variant.
Quite a bit better, thanks. Martin
Richard.Richard.Martin+Enabled at level @option{-O1} and higher, except for @option{-Og}. + @item -fsplit-loops @opindex fsplit-loops Split a loop into two if it contains a condition that's always true diff --git a/gcc/opts.c b/gcc/opts.c index f159bb35130..25282f71a3b 100644 --- a/gcc/opts.c +++ b/gcc/opts.c @@ -575,6 +575,7 @@ static const struct default_options default_options_table[] = { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_fif_conversion2, NULL, 1 }, { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_finline_functions_called_once, NULL, 1 }, { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_fmove_loop_invariants, NULL, 1 }, + { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_fmove_loop_stores, NULL, 1 }, { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_fssa_phiopt, NULL, 1 }, { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_fipa_modref, NULL, 1 }, { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_ftree_bit_ccp, NULL, 1 }, diff --git a/gcc/tree-ssa-loop-im.c b/gcc/tree-ssa-loop-im.c index e7a3050ba9d..9ac390b9a4b 100644 --- a/gcc/tree-ssa-loop-im.c +++ b/gcc/tree-ssa-loop-im.c @@ -3258,7 +3258,7 @@ pass_lim::execute (function *fun)if (number_of_loops (fun) <= 1)return 0; - unsigned int todo = loop_invariant_motion_in_fun (fun, true); + unsigned int todo = loop_invariant_motion_in_fun (fun, flag_move_loop_stores);if (!in_loop_pipeline)loop_optimizer_finalize ();
