[gcc(refs/vendors/ibm/heads/perf)] One more patch for PR93564: Prefer smaller hard regno when we do not honor reg alloc order.

[Jiu Fu Guo]

https://gcc.gnu.org/g:f3ce088645e5305d932380c7520809181b2d2eb9

commit f3ce088645e5305d932380c7520809181b2d2eb9
Author: Vladimir N. Makarov <vmakarov@redhat.com>
Date:   Fri Feb 28 11:27:30 2020 -0500

    One more patch for PR93564: Prefer smaller hard regno when we do not honor reg alloc order.
    
    2020-02-28  Vladimir Makarov  <vmakarov@redhat.com>
    
            PR rtl-optimization/93564
            * ira-color.c (assign_hard_reg): Prefer smaller hard regno when we
            do not honor reg alloc order.

Diff:
---
 gcc/ChangeLog   | 6 ++++++
 gcc/ira-color.c | 4 +++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f6a9ae2375e..1451807f7d9 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2020-02-28  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/93564
+	* ira-color.c (assign_hard_reg): Prefer smaller hard regno when we
+	do not honor reg alloc order.
+
 2020-02-27  Joel Hutton  <Joel.Hutton@arm.com>
 
 	PR target/87612
diff --git a/gcc/ira-color.c b/gcc/ira-color.c
index 0ffdd192020..a2bf108c38e 100644
--- a/gcc/ira-color.c
+++ b/gcc/ira-color.c
@@ -1925,7 +1925,9 @@ assign_hard_reg (ira_allocno_t a, bool retry_p)
 	}
       if (min_cost > cost)
 	min_cost = cost;
-      if (min_full_cost > full_cost)
+      if (min_full_cost > full_cost
+	  || (!HONOR_REG_ALLOC_ORDER && min_full_cost == full_cost
+	      && best_hard_regno > hard_regno))
 	{
 	  min_full_cost = full_cost;
 	  best_hard_regno = hard_regno;