From: liuhongt <hongtao.liu@intel.com>
Date: Mon, 3 Apr 2023 02:54:55 +0000 (+0800)
Subject: Check hard_regno_mode_ok before setting lowest memory move cost for the mode with... 
X-Git-Tag: basepoints/gcc-15~10082
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=727be65ec40e119a7c864bfaa5d6a73547863c06;p=thirdparty%2Fgcc.git

Check hard_regno_mode_ok before setting lowest memory move cost for the mode with different reg classes.

There's a potential performance issue when backend returns some
unreasonable value for the mode which can be never be allocate with
reg class.

gcc/ChangeLog:

	PR rtl-optimization/109351
	* ira.cc (setup_class_subset_and_memory_move_costs): Check
	hard_regno_mode_ok before setting lowest memory move cost for
	the mode with different reg classes.
---

diff --git a/gcc/ira.cc b/gcc/ira.cc
index 6c7f4901e4cc..02dea5d49ee7 100644
--- a/gcc/ira.cc
+++ b/gcc/ira.cc
@@ -588,6 +588,10 @@ setup_class_subset_and_memory_move_costs (void)
 	    /* Costs for NO_REGS are used in cost calculation on the
 	       1st pass when the preferred register classes are not
 	       known yet.  In this case we take the best scenario.  */
+	    if (!targetm.hard_regno_mode_ok (ira_class_hard_regs[cl][0],
+					     (machine_mode) mode))
+	      continue;
+
 	    if (ira_memory_move_cost[mode][NO_REGS][0]
 		> ira_memory_move_cost[mode][cl][0])
 	      ira_max_memory_move_cost[mode][NO_REGS][0]