On May 26, 2018 11:32:29 AM GMT+02:00, Allan Sandfeld Jensen
<li...@carewolf.com> wrote:
>I brought this subject up earlier, and was told to suggest it again for
>gcc 9,
>so I have attached the preliminary changes.
>
>My studies have show that with generic x86-64 optimization it reduces
>binary
>size with around 0.5%, and when optimizing for x64 targets with SSE4 or
>
>better, it reduces binary size by 2-3% on average. The performance
>changes are
>negligible however*, and I haven't been able to detect changes in
>compile time
>big enough to penetrate general noise on my platform, but perhaps
>someone has
>a better setup for that?
>
>* I believe that is because it currently works best on non-optimized
>code, it
>is better at big basic blocks doing all kinds of things than tightly
>written
>inner loops.
>
>Anythhing else I should test or report?
If you have access to SPEC CPU I'd like to see performance, size and
compile-time effects of the patch on that. Embedded folks may want to rhn their
favorite benchmark and report results as well.
Richard.
>Best regards
>'Allan
>
>
>diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
>index beba295bef5..05851229354 100644
>--- a/gcc/doc/invoke.texi
>+++ b/gcc/doc/invoke.texi
>@@ -7612,6 +7612,7 @@ also turns on the following optimization flags:
> -fstore-merging @gol
> -fstrict-aliasing @gol
> -ftree-builtin-call-dce @gol
>+-ftree-slp-vectorize @gol
> -ftree-switch-conversion -ftree-tail-merge @gol
> -fcode-hoisting @gol
> -ftree-pre @gol
>@@ -7635,7 +7636,6 @@ by @option{-O2} and also turns on the following
>optimization flags:
> -floop-interchange @gol
> -floop-unroll-and-jam @gol
> -fsplit-paths @gol
>--ftree-slp-vectorize @gol
> -fvect-cost-model @gol
> -ftree-partial-pre @gol
> -fpeel-loops @gol
>@@ -8932,7 +8932,7 @@ Perform loop vectorization on trees. This flag is
>
>enabled by default at
> @item -ftree-slp-vectorize
> @opindex ftree-slp-vectorize
>Perform basic block vectorization on trees. This flag is enabled by
>default
>at
>-@option{-O3} and when @option{-ftree-vectorize} is enabled.
>+@option{-O2} or higher, and when @option{-ftree-vectorize} is enabled.
>
> @item -fvect-cost-model=@var{model}
> @opindex fvect-cost-model
>diff --git a/gcc/opts.c b/gcc/opts.c
>index 33efcc0d6e7..11027b847e8 100644
>--- a/gcc/opts.c
>+++ b/gcc/opts.c
>@@ -523,6 +523,7 @@ static const struct default_options
>default_options_table[] =
> { OPT_LEVELS_2_PLUS, OPT_fipa_ra, NULL, 1 },
> { OPT_LEVELS_2_PLUS, OPT_flra_remat, NULL, 1 },
> { OPT_LEVELS_2_PLUS, OPT_fstore_merging, NULL, 1 },
>+ { OPT_LEVELS_2_PLUS, OPT_ftree_slp_vectorize, NULL, 1 },
>
> /* -O3 optimizations. */
> { OPT_LEVELS_3_PLUS, OPT_ftree_loop_distribute_patterns, NULL, 1 },
>@@ -539,7 +540,6 @@ static const struct default_options
>default_options_table[] =
> { OPT_LEVELS_3_PLUS, OPT_floop_unroll_and_jam, NULL, 1 },
> { OPT_LEVELS_3_PLUS, OPT_fgcse_after_reload, NULL, 1 },
> { OPT_LEVELS_3_PLUS, OPT_ftree_loop_vectorize, NULL, 1 },
>- { OPT_LEVELS_3_PLUS, OPT_ftree_slp_vectorize, NULL, 1 },
>{ OPT_LEVELS_3_PLUS, OPT_fvect_cost_model_, NULL,
>VECT_COST_MODEL_DYNAMIC
>},
> { OPT_LEVELS_3_PLUS, OPT_fipa_cp_clone, NULL, 1 },
> { OPT_LEVELS_3_PLUS, OPT_ftree_partial_pre, NULL, 1 },
