re PR rtl-optimization/38711 (ira should not be using df-lr except at -O1.)

	PR rtl-optimization/38711
	* ira.c (ira): Remove DF_LIVE if the problem is in the stack.
	(do_reload): Add it back at the end for -O2 and higher.

	* function.c (thread_prologue_and_epilogue_insns): Use
	REG_SET_TO_HARD_REG_SET instead of CLEAR_HARD_REG_SET and
	reg_set_to_hard_reg_set.

From-SVN: r192890

gcc/ChangeLog

+2012-10-28  Steven Bosscher  <steven@gcc.gnu.org>
+
+	PR rtl-optimization/38711
+	* ira.c (ira): Remove DF_LIVE if the problem is in the stack.
+	(do_reload): Add it back at the end for -O2 and higher.
+
+	* function.c (thread_prologue_and_epilogue_insns): Use
+	REG_SET_TO_HARD_REG_SET instead of CLEAR_HARD_REG_SET and
+	reg_set_to_hard_reg_set.
+
 2012-10-28  Jan Hubicka  <jh@suse.cz>
 
 	* ipa-inline.c (edge_badness): Reduce precision; use scc hints.

gcc/function.c

@@ -6176,8 +6176,7 @@ thread_prologue_and_epilogue_insns (void)
 	  CLEAR_HARD_REG_BIT (prologue_clobbered, STACK_POINTER_REGNUM);
 	  if (frame_pointer_needed)
 	    CLEAR_HARD_REG_BIT (prologue_clobbered, HARD_FRAME_POINTER_REGNUM);
-	  CLEAR_HARD_REG_SET (live_on_edge);
-	  reg_set_to_hard_reg_set (&live_on_edge,
+	  REG_SET_TO_HARD_REG_SET (live_on_edge,
 				   df_get_live_in (entry_edge->dest));
 	  if (hard_reg_set_intersect_p (live_on_edge, prologue_clobbered))
 	    {

gcc/ira.c

@@ -4399,6 +4399,16 @@ ira (FILE *f)
   setup_prohibited_mode_move_regs ();
 
   df_note_add_problem ();
+
+  /* DF_LIVE can't be used in the register allocator, too many other
+     parts of the compiler depend on using the "classic" liveness
+     interpretation of the DF_LR problem.  See PR38711.
+     Remove the problem, so that we don't spend time updating it in
+     any of the df_analyze() calls during IRA/LRA.  */
+  if (optimize > 1)
+    df_remove_problem (df_live);
+  gcc_checking_assert (df_live == NULL);
+
 #ifdef ENABLE_CHECKING
   df->changeable_flags |= DF_VERIFY_SCHEDULED;
 #endif
@@ -4678,6 +4688,12 @@ do_reload (void)
   df_scan_alloc (NULL);
   df_scan_blocks ();
 
+  if (optimize > 1)
+    {
+      df_live_add_problem ();
+      df_live_set_all_dirty ();
+    }
+
   if (optimize)
     df_analyze ();