From 3686c5158dd58602f87af7c33d2d409e3ee7b53e Mon Sep 17 00:00:00 2001 From: Andreas Krebbel Date: Fri, 20 Sep 2019 09:23:50 +0000 Subject: [PATCH] re PR rtl-optimization/88751 (Performance regression reload vs lra) Fix PR88751 This patch implements a small improvement for the heuristic in lra which decides when it has to activate the simpler register allocation algorithm. gcc/ChangeLog: 2019-09-20 Andreas Krebbel Backport from mainline 2019-06-06 Andreas Krebbel PR rtl-optimization/88751 * ira.c (ira): Use the number of the actually referenced registers when calculating the threshold. From-SVN: r275993 --- gcc/ChangeLog | 9 +++++++++ gcc/ira.c | 9 ++++++++- 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index ad4384a37c3b..533ab1c3f13a 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,12 @@ +2019-09-20 Andreas Krebbel + + Backport from mainline + 2019-06-06 Andreas Krebbel + + PR rtl-optimization/88751 + * ira.c (ira): Use the number of the actually referenced registers + when calculating the threshold. + 2019-09-11 Eric Botcazou PR rtl-optimization/89795 diff --git a/gcc/ira.c b/gcc/ira.c index 5265ab174880..4925cc713b06 100644 --- a/gcc/ira.c +++ b/gcc/ira.c @@ -5160,6 +5160,8 @@ ira (FILE *f) int ira_max_point_before_emit; bool saved_flag_caller_saves = flag_caller_saves; enum ira_region saved_flag_ira_region = flag_ira_region; + unsigned int i; + int num_used_regs = 0; clear_bb_flags (); @@ -5175,12 +5177,17 @@ ira (FILE *f) ira_conflicts_p = optimize > 0; + /* Determine the number of pseudos actually requiring coloring. */ + for (i = FIRST_PSEUDO_REGISTER; i < DF_REG_SIZE (df); i++) + num_used_regs += !!(DF_REG_USE_COUNT (i) + DF_REG_DEF_COUNT (i)); + /* If there are too many pseudos and/or basic blocks (e.g. 10K pseudos and 10K blocks or 100K pseudos and 1K blocks), we will use simplified and faster algorithms in LRA. */ lra_simple_p = (ira_use_lra_p - && max_reg_num () >= (1 << 26) / last_basic_block_for_fn (cfun)); + && num_used_regs >= (1 << 26) / last_basic_block_for_fn (cfun)); + if (lra_simple_p) { /* It permits to skip live range splitting in LRA. */ -- 2.47.2