[PATCH, 4.5] Fix PR 44914

[Martin Jambor]

Hi,

fix for PR 44914 on the 4.5 branch needs to be a little bit different
because of how the functions are organized there.  In particular,
scan_function is not split into three different ones and it already
returns a value.  Therefore I resorted to a global variable to flag
that CFG has been changed.  This is a bit ugly but it is not the first
global variable that we use (there already is
encountered_unchangable_recursive_call) and it is fortunately used
only in a very simple way.

Bootstrapped and tested on the branch on x86_64-linux, OK for trunk?

Thanks,

Martin


2010-08-02  Martin Jambor  <mjambor@suse.cz>

	PR tree-optimization/44914
	* tree-sra.c (cfg_changed): New variable.
	(sra_initialize): Initialize cgf_changed to false.
	(scan_function): Set cfg_changed if cfg was changed.
	(perform_intra_sra): Return also TODO_update_sa if cfg was changed.
	(ipa_early_sra): Likewise.

	* testsuite/g++.dg/tree-ssa/pr44914.C: New test

Index: gcc-4_5-branch/gcc/tree-sra.c
===================================================================
--- gcc-4_5-branch.orig/gcc/tree-sra.c
+++ gcc-4_5-branch/gcc/tree-sra.c
@@ -276,6 +276,9 @@ static bool encountered_apply_args;
    arguments than formal parameters..  */
 static bool encountered_unchangable_recursive_call;
 
+/* Set by scan_function when it changes the control flow graph.  */
+static bool cfg_changed;
+
 /* This is a table in which for each basic block and parameter there is a
    distance (offset + size) in that parameter which is dereferenced and
    accessed in that BB.  */
@@ -570,6 +573,7 @@ sra_initialize (void)
   memset (&sra_stats, 0, sizeof (sra_stats));
   encountered_apply_args = false;
   encountered_unchangable_recursive_call = false;
+  cfg_changed = false;
 }
 
 /* Hook fed to pointer_map_traverse, deallocate stored vectors.  */
@@ -1114,8 +1118,6 @@ scan_function (bool (*scan_expr) (tree *
 
   FOR_EACH_BB (bb)
     {
-      bool bb_changed = false;
-
       if (handle_ssa_defs)
 	for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 	  ret |= handle_ssa_defs (gsi_stmt (gsi), data);
@@ -1220,21 +1222,15 @@ scan_function (bool (*scan_expr) (tree *
 
 	      if (!analysis_stage)
 		{
-		  bb_changed = true;
 		  update_stmt (stmt);
-		  maybe_clean_eh_stmt (stmt);
+		  if (maybe_clean_eh_stmt (stmt)
+		      && gimple_purge_dead_eh_edges (bb))
+		    cfg_changed = true;
 		}
 	    }
-	  if (deleted)
-	    bb_changed = true;
-	  else
-	    {
-	      gsi_next (&gsi);
-	      ret = true;
-	    }
+	  if (!deleted)
+	    gsi_next (&gsi);
 	}
-      if (!analysis_stage && bb_changed && sra_mode == SRA_MODE_EARLY_IPA)
-	gimple_purge_dead_eh_edges (bb);
     }
 
   return ret;
@@ -2871,7 +2867,10 @@ perform_intra_sra (void)
   statistics_counter_event (cfun, "Separate LHS and RHS handling",
 			    sra_stats.separate_lhs_rhs_handling);
 
-  ret = TODO_update_ssa;
+  if (cfg_changed)
+    ret = TODO_update_ssa | TODO_cleanup_cfg;
+  else
+    ret = TODO_update_ssa;
 
  out:
   sra_deinitialize ();
@@ -4236,7 +4235,10 @@ ipa_early_sra (void)
 
   modify_function (node, adjustments);
   VEC_free (ipa_parm_adjustment_t, heap, adjustments);
-  ret = TODO_update_ssa;
+  if (cfg_changed)
+    ret = TODO_update_ssa | TODO_cleanup_cfg;
+  else
+    ret = TODO_update_ssa;
 
   statistics_counter_event (cfun, "Unused parameters deleted",
 			    sra_stats.deleted_unused_parameters);
Index: gcc-4_5-branch/gcc/testsuite/g++.dg/tree-ssa/pr44914.C
===================================================================
--- /dev/null
+++ gcc-4_5-branch/gcc/testsuite/g++.dg/tree-ssa/pr44914.C
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fipa-sra -fnon-call-exceptions" } */
+
+struct A
+{
+  ~A () { }
+};
+
+struct B
+{
+  A a;
+  int i;
+  void f (int) { }
+  B ()
+  {
+    f (i);
+  }
+};
+
+B b;