[PATCH] i386: Disable param ira-consider-dup-in-all-alts [PR100328]

["Kewen.Lin" <linkw@linux.ibm.com>]

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Hi,

With Hongtao's help (thanks), we got the SPEC2017 performance
evaluation result on x86_64 (see [1]), this new parameter
ira-consider-dup-in-all-alts has negative effects on i386.
Since we observed it can benefit ports aarch64 and rs6000, the
param is set as 1 by default, this patch is to disable it on
i386 explicitly to avoid performance degradation there.

Bootstrapped & regtested on x86_64-redhat-linux.

Is it ok for trunk?

BR,
Kewen

[1] https://gcc.gnu.org/pipermail/gcc-patches/2021-June/573986.html
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From 457c7b3032e20ea0f9d8c8d2980e7da6daeedb13 Mon Sep 17 00:00:00 2001
From: Kewen Lin <linkw@linux.ibm.com>
Date: Mon, 21 Jun 2021 22:51:09 -0500
Subject: [PATCH 2/2] i386: Disable param ira-consider-dup-in-all-alts
 [PR100328]

With Hongtao's SPEC2017 performance evaluation result here:
https://gcc.gnu.org/pipermail/gcc-patches/2021-June/573986.html
this new parameter ira-consider-dup-in-all-alts has negative
effects on i386, this patch is to disable it explicitly on
i386.

Bootstrapped & regtested on x86_64-redhat-linux.

gcc/ChangeLog:

	PR rtl-optimization/100328
	* config/i386/i386-options.c (ix86_option_override_internal):
	Set param_ira_consider_dup_in_all_alts to 0.
---
 gcc/config/i386/i386-options.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gcc/config/i386/i386-options.c b/gcc/config/i386/i386-options.c
index 0eccb549c22..7a35c468da3 100644
--- a/gcc/config/i386/i386-options.c
+++ b/gcc/config/i386/i386-options.c
@@ -2831,6 +2831,8 @@ ix86_option_override_internal (bool main_args_p,
   if (ix86_indirect_branch != indirect_branch_keep)
     SET_OPTION_IF_UNSET (opts, opts_set, flag_jump_tables, 0);
 
+  SET_OPTION_IF_UNSET (opts, opts_set, param_ira_consider_dup_in_all_alts, 0);
+
   return true;
 }
 
-- 
2.17.1