From patchwork Wed Feb  8 15:01:56 2012
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Subject: haifa-sched: Fix problems with cc0 in prune_ready_list
Date: Wed, 08 Feb 2012 05:01:56 -0000
From: Bernd Schmidt <bernds@codesourcery.com>
X-Patchwork-Id: 140150
Message-Id: <4F328E64.3060601@codesourcery.com>
To: GCC Patches <gcc-patches@gcc.gnu.org>

We found a scheduler problem while testing Coldfire targets. The
prune_ready_list function I introduced doesn't take SCHED_GROUPs into
account, which can lead to a random insn being scheduled between a cc0
setter and user. The patch below fixes it, OK? (Bootstrapped & tested
i686-linux).


Bernd
* haifa-sched.c (prune_ready_list): Ensure that if there is a
	sched-group insn, it either remains alone or the entire list is
	pruned.


Index: gcc/haifa-sched.c
===================================================================
--- gcc/haifa-sched.c	(revision 357962)
+++ gcc/haifa-sched.c	(working copy)
@@ -3959,6 +3959,7 @@ prune_ready_list (state_t temp_state, bo
 		  bool shadows_only_p, bool modulo_epilogue_p)
 {
   int i;
+  bool sched_group_found = false;
 
  restart:
   for (i = 0; i < ready.n_ready; i++)
@@ -3967,13 +3968,27 @@ prune_ready_list (state_t temp_state, bo
       int cost = 0;
       const char *reason = "resource conflict";
 
-      if (modulo_epilogue_p && !DEBUG_INSN_P (insn)
-	  && INSN_EXACT_TICK (insn) == INVALID_TICK)
+      if (DEBUG_INSN_P (insn))
+	continue;
+
+      if (SCHED_GROUP_P (insn) && !sched_group_found)
+	{
+	  sched_group_found = true;
+	  if (i > 0)
+	    goto restart;
+	}
+
+      if (sched_group_found && !SCHED_GROUP_P (insn))
+	{
+	  cost = 1;
+	  reason = "not in sched group";
+	}
+      else if (modulo_epilogue_p && INSN_EXACT_TICK (insn) == INVALID_TICK)
 	{
 	  cost = max_insn_queue_index;
 	  reason = "not an epilogue insn";
 	}
-      if (shadows_only_p && !DEBUG_INSN_P (insn) && !SHADOW_P (insn))
+      else if (shadows_only_p && !SHADOW_P (insn))
 	{
 	  cost = 1;
 	  reason = "not a shadow";