re PR bootstrap/63740 (GCC 4.9.2 bootstrap fails on ARM, haifa-sched.c:6507:1:…

re PR bootstrap/63740 (GCC 4.9.2 bootstrap fails on ARM, haifa-sched.c:6507:1: internal compiler error: in lra_create)

2015-06-22  Vladimir Makarov  <vmakarov@redhat.com>

	PR bootstrap/63740
	* lra-lives.c (process_bb_lives): Check insn copying the same
	reload pseudo and don't create a copy for it.

From-SVN: r224753

gcc/ChangeLog

+2015-06-22  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR bootstrap/63740
+	* lra-lives.c (process_bb_lives): Check insn copying the same
+	reload pseudo and don't create a copy for it.
+
 2015-06-22  Tom de Vries  <tom@codesourcery.com>
 
 	* tree-parloops.c (transform_to_exit_first_loop_alt): Add update_stmt

gcc/lra-lives.c

@@ -768,7 +768,15 @@ process_bb_lives (basic_block bb, int &curr_point, bool dead_insn_p)
 	  dst_regno = REGNO (SET_DEST (set));
 	  if (dst_regno >= lra_constraint_new_regno_start
 	      && src_regno >= lra_constraint_new_regno_start)
-	    lra_create_copy (dst_regno, src_regno, freq);
+	    {
+	      /* It might be still an original (non-reload) insn with
+		 one unused output and a constraint requiring to use
+		 the same reg for input/output operands. In this case
+		 dst_regno and src_regno have the same value, we don't
+		 need a misleading copy for this case.  */
+	      if (dst_regno != src_regno)
+		lra_create_copy (dst_regno, src_regno, freq);
+	    }
 	  else if (dst_regno >= lra_constraint_new_regno_start)
 	    {
 	      if ((hard_regno = src_regno) >= FIRST_PSEUDO_REGISTER)