2007-09-21 Richard Guenther <rguenther@suse.de>

	PR tree-optimization/33508
	* tree-ssa-alias.c (mark_aliases_call_clobbered): Avoid
	quadratic loop by keeping a bitmap of variables we have
	to clobber all subvariables for.
	(set_initial_properties): Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@128645 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d6eeb98af3e59bc0dcfbf0e8bf076f070114f517..9a192e602503681d271b3a930f1f3b8fb0517dcf 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2007-09-21  Richard Guenther  <rguenther@suse.de>
+
+       PR tree-optimization/33508
+       * tree-ssa-alias.c (mark_aliases_call_clobbered): Avoid
+       quadratic loop by keeping a bitmap of variables we have
+       to clobber all subvariables for.
+       (set_initial_properties): Likewise.
+
 2007-09-21  Richard Sandiford  <rsandifo@nildram.co.uk>
 
        * config/mips/t-sde (TARGET_LIBGCC2_CFLAGS): Delete.

diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 52ca86b48df14d67600ab00067ffe05e868848b6..1ff3821ed5ac59e72a8de1a5c663300449343103 100644 (file)
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -364,7 +364,7 @@ add_to_worklist (tree alias, VEC (tree, heap) **worklist,
 static void
 mark_aliases_call_clobbered (tree tag, VEC (tree, heap) **worklist,
                             VEC (int, heap) **worklist2,
-                            bitmap on_worklist)
+                            bitmap on_worklist, bitmap queued)
 {
   bitmap aliases;
   bitmap_iterator bi;
@@ -387,13 +387,7 @@ mark_aliases_call_clobbered (tree tag, VEC (tree, heap) **worklist,
         in order to allow C/C++ tricks that involve
         pointer arithmetic to work.  */
       if (TREE_CODE (entry) == STRUCT_FIELD_TAG)
-       {
-         subvar_t svars;
-         svars = get_subvars_for_var (SFT_PARENT_VAR (entry));
-         for (; svars; svars = svars->next)
-           if (!unmodifiable_var_p (entry))
-             mark_call_clobbered (svars->var, ta->escape_mask);
-       }
+       bitmap_set_bit (queued, DECL_UID (SFT_PARENT_VAR (entry)));
       else if (!unmodifiable_var_p (entry))
        {
          add_to_worklist (entry, worklist, worklist2, ta->escape_mask,
@@ -401,6 +395,18 @@ mark_aliases_call_clobbered (tree tag, VEC (tree, heap) **worklist,
          mark_call_clobbered (entry, ta->escape_mask);
        }
     }
+  if (!bitmap_empty_p (queued))
+    {
+      EXECUTE_IF_SET_IN_BITMAP (queued, 0, i, bi)
+       {
+         subvar_t svars;
+         svars = get_subvars_for_var (referenced_var (i));
+         for (; svars; svars = svars->next)
+           if (!unmodifiable_var_p (svars->var))
+              mark_call_clobbered (svars->var, ta->escape_mask);
+       }
+      bitmap_clear (queued);
+    }
 }
 
 /* Tags containing global vars need to be marked as global.
@@ -508,6 +514,11 @@ set_initial_properties (struct alias_info *ai)
   referenced_var_iterator rvi;
   tree var;
   tree ptr;
+  bitmap queued;
+
+  /* Temporary bitmap to avoid quadratic behavior in marking
+     call clobbers.  */
+  queued = BITMAP_ALLOC (&alias_bitmap_obstack);
 
   FOR_EACH_REFERENCED_VAR (var, rvi)
     {
@@ -557,15 +568,22 @@ set_initial_properties (struct alias_info *ai)
                     in order to allow C/C++ tricks that involve
                     pointer arithmetic to work.  */
                  if (TREE_CODE (alias) == STRUCT_FIELD_TAG)
+                   bitmap_set_bit (queued, DECL_UID (SFT_PARENT_VAR (alias)));
+                 else if (!unmodifiable_var_p (alias))
+                   mark_call_clobbered (alias, pi->escape_mask);
+               }
+             /* Process variables we need to clobber all parts of.  */
+             if (!bitmap_empty_p (queued))
+               {
+                 EXECUTE_IF_SET_IN_BITMAP (queued, 0, j, bi)
                    {
                      subvar_t svars;
-                     svars = get_subvars_for_var (SFT_PARENT_VAR (alias));
+                     svars = get_subvars_for_var (referenced_var (j));
                      for (; svars; svars = svars->next)
-                       if (!unmodifiable_var_p (alias))
+                       if (!unmodifiable_var_p (svars->var))
                          mark_call_clobbered (svars->var, pi->escape_mask);
                    }
-                 else if (!unmodifiable_var_p (alias))
-                   mark_call_clobbered (alias, pi->escape_mask);
+                 bitmap_clear (queued);
                }
            }
        }
@@ -600,6 +618,8 @@ set_initial_properties (struct alias_info *ai)
          MTAG_GLOBAL (tag) = true;
        }
     }
+
+  BITMAP_FREE (queued);
 }
 
 /* Compute which variables need to be marked call clobbered because
@@ -611,10 +631,11 @@ compute_call_clobbered (struct alias_info *ai)
 {
   VEC (tree, heap) *worklist = NULL;
   VEC (int,heap) *worklist2 = NULL;
-  bitmap on_worklist;
+  bitmap on_worklist, queued;
 
   timevar_push (TV_CALL_CLOBBER);
   on_worklist = BITMAP_ALLOC (NULL);
+  queued = BITMAP_ALLOC (NULL);
     
   set_initial_properties (ai);
   init_transitive_clobber_worklist (&worklist, &worklist2, on_worklist);
@@ -626,11 +647,12 @@ compute_call_clobbered (struct alias_info *ai)
       bitmap_clear_bit (on_worklist, DECL_UID (curr));
       mark_call_clobbered (curr, reason);
       mark_aliases_call_clobbered (curr, &worklist, &worklist2,
-                                  on_worklist);
+                                  on_worklist, queued);
     }
   VEC_free (tree, heap, worklist);
   VEC_free (int, heap, worklist2);
   BITMAP_FREE (on_worklist);
+  BITMAP_FREE (queued);
   compute_tag_properties ();
   timevar_pop (TV_CALL_CLOBBER);
 }