2014-08-14  Jakub Jelinek  <jakub@redhat.com>

	PR target/62025
	* sched-deps.c (find_inc): Limit the test for inc_insn defs
	vs. mem_insn uses to !backwards case only.  Give up also if
	any mem_insn def is used by inc_insn or if non-clobber
	mem_insn def in backwards case is clobbered by inc_insn.

--- gcc/sched-deps.c.jj	2014-08-12 17:06:26.000000000 +0200
+++ gcc/sched-deps.c	2014-08-14 00:09:38.000000000 +0200
@@ -4746,23 +4746,70 @@ find_inc (struct mem_inc_info *mii, bool
 			     "inc conflicts with store failure.\n");
 		  goto next;
 		}
+	      else
+		{
+		  df_ref *use_rec, *def2_rec;
+		  for (use_rec = DF_INSN_USES (mii->inc_insn);
+		       *use_rec; use_rec++)
+		    {
+		      df_ref use = *use_rec;
+		      if (reg_overlap_mentioned_p (DF_REF_REG (def),
+						   DF_REF_REG (use)))
+			{
+			  if (sched_verbose >= 5)
+			    fprintf (sched_dump,
+				     "mem def conflict with inc use "
+				     "failure.\n");
+			  goto next;
+			}
+		    }
+		  /* If both inc_insn and mem_insn clobber the same register,
+		     it is fine, but avoid the case where mem_insn e.g.
+		     sets CC and originally earlier inc_insn clobbers it.  */
+		  if ((DF_REF_FLAGS (def) & DF_REF_MUST_CLOBBER) == 0
+		      && backwards)
+		    for (def2_rec = DF_INSN_DEFS (mii->inc_insn);
+			 *def2_rec; def2_rec++)
+		      {
+			df_ref def2 = *def2_rec;
+			if (reg_overlap_mentioned_p (DF_REF_REG (def),
+						     DF_REF_REG (def2)))
+			  {
+			    if (sched_verbose >= 5)
+			      fprintf (sched_dump,
+				       "mem def conflict with inc def "
+				       "failure.\n");
+			    goto next;
+			  }
+		      }
+		}
 	    }
 
 	  /* The inc instruction could have clobbers, make sure those
-	     registers are not used in mem insn.  */
-	  for (def_rec = DF_INSN_DEFS (mii->inc_insn); *def_rec; def_rec++)
-	    if (!reg_overlap_mentioned_p (DF_REF_REG (*def_rec), mii->mem_reg0))
+	     registers are not used in mem insn, if mem_insn is originally
+	     earlier than inc_insn.  */
+	  if (!backwards)
+	    for (def_rec = DF_INSN_DEFS (mii->inc_insn); *def_rec; def_rec++)
 	      {
-		df_ref *use_rec;
-		for (use_rec = DF_INSN_USES (mii->mem_insn); *use_rec; use_rec++)
-		  if (reg_overlap_mentioned_p (DF_REF_REG (*def_rec),
-					       DF_REF_REG (*use_rec)))
-		    {
-		      if (sched_verbose >= 5)
-			fprintf (sched_dump,
-				 "inc clobber used in store failure.\n");
-		      goto next;
-		    }
+		df_ref def = *def_rec;
+		if (!reg_overlap_mentioned_p (DF_REF_REG (def), mii->mem_reg0))
+		  {
+		    df_ref *use_rec;
+		    for (use_rec = DF_INSN_USES (mii->mem_insn);
+			 *use_rec; use_rec++)
+		      {
+			df_ref use = *use_rec;
+			if (reg_overlap_mentioned_p (DF_REF_REG (def),
+						     DF_REF_REG (use)))
+			  {
+			    if (sched_verbose >= 5)
+			      fprintf (sched_dump,
+				       "inc def conflict with mem use "
+				       "failure.\n");
+			    goto next;
+			  }
+		      }
+		  }
 	      }
 
 	  newaddr = mii->inc_input;