Update the patch so it can apply. Tested on spec2017 fprate cases again. With option "-funroll-loops -Ofast -flto", the improvements of 1-copy run are:
Ampere1:
508.namd_r 4.26%
510.parest_r 2.55%
Overall 0.54%
Intel Xeon:
503.bwaves_r 1.3%
508.namd_r 1.58%
overall 0.42%
Thanks,
Di Zhao
> -----Original Message-----
> From: Di Zhao OS
> Sent: Friday, June 16, 2023 4:51 PM
> To: gcc-patches@gcc.gnu.org
> Subject: [PATCH] tree-optimization/110279- Check for nested FMA chains in
> reassoc
>
> This patch is to fix the regressions found in SPEC2017 fprate cases
> on aarch64.
>
> 1. Reused code in pass widening_mul to check for nested FMA chains
> (those connected by MULT_EXPRs), since re-writing to parallel
> generates worse codes.
>
> 2. Avoid re-arrange to produce less FMA chains that can be slow.
>
> Tested on ampere1 and neoverse-n1, this fixed the regressions in
> 508.namd_r and 510.parest_r 1 copy run. While I'm still collecting data
> on x86 machines we have, I'd like to know what do you think of this.
>
> (Previously I tried to improve things with FMA by adding a widening_mul
> pass before reassoc2 for it's easier to recognize different patterns
> of FMA chains and decide whether to split them. But I suppose handling
> them all in reassoc pass is more efficient.)
>
> Thanks,
> Di Zhao
>
> ---
> gcc/ChangeLog:
>
> * tree-ssa-math-opts.cc (convert_mult_to_fma_1): Add new parameter.
> Support new mode that merely do the checking.
> (struct fma_transformation_info): Moved to header.
> (class fma_deferring_state): Moved to header.
> (convert_mult_to_fma): Add new parameter.
> * tree-ssa-math-opts.h (struct fma_transformation_info):
> (class fma_deferring_state): Moved from .cc.
> (convert_mult_to_fma): Add function decl.
> * tree-ssa-reassoc.cc (rewrite_expr_tree_parallel):
> (rank_ops_for_fma): Return -1 if nested FMAs are found.
> (reassociate_bb): Avoid rewriting to parallel if nested FMAs are
> found.
0001-Check-for-nested-FMA-chains-in-reassoc.patch
Description: 0001-Check-for-nested-FMA-chains-in-reassoc.patch
