From: Vladimir N. Makarov <vmakarov@redhat.com>
Date: Wed, 19 Mar 2025 20:06:41 +0000 (-0400)
Subject: [PR119270][IRA]: Ignore equiv init insns for cost calculation for invariants only
X-Git-Tag: basepoints/gcc-16~1104
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6c443e128802bd93158a3db7c4edf5fc1fc76c8d;p=thirdparty%2Fgcc.git

[PR119270][IRA]: Ignore equiv init insns for cost calculation for invariants only

My previous patch for PR114991 contains code ignoring equiv init insns
for increasing cost of usage the equivalence.  Although common sense says
it is right thing to do, this results in more aggressive usage of
memory equivalence and significant performance degradation of SPEC2017
cactuBSSM.  Given patch restores previous cost calculation for all
equivalences except for invariant ones.

gcc/ChangeLog:

	PR target/119270
	* ira-costs.cc (calculate_equiv_gains): Ignore equiv init insns
	only for invariants.
---

diff --git a/gcc/ira-costs.cc b/gcc/ira-costs.cc
index 70cba942a7b..faf706ca5dd 100644
--- a/gcc/ira-costs.cc
+++ b/gcc/ira-costs.cc
@@ -1926,12 +1926,15 @@ calculate_equiv_gains (void)
 	      || !bitmap_bit_p (&equiv_pseudos, regno))
 	    continue;
 
-	  rtx_insn_list *x;
-	  for (x = ira_reg_equiv[regno].init_insns; x != NULL; x = x->next ())
-	    if (insn == x->insn ())
-	      break;
-	  if (x != NULL)
-	    continue; /* skip equiv init insn */
+	  if (ira_reg_equiv[regno].invariant != NULL)
+	    {
+	      rtx_insn_list *x = ira_reg_equiv[regno].init_insns;
+	      for (; x != NULL; x = x->next ())
+		if (insn == x->insn ())
+		  break;
+	      if (x != NULL)
+		continue; /* skip equiv init insn for invariant */
+	    }
 
 	  rtx subst = ira_reg_equiv[regno].memory;