tree-ssa-structalias.c (lookup_vi_for_tree): Declare.

2008-07-04  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-structalias.c (lookup_vi_for_tree): Declare.
	(do_sd_constraint): Handle a dereference of ESCAPED and CALLUSED
	properly to compute the reachability set if we do field-sensitive PTA.
	* invoke.texi (max-fields-for-field-sensitive): Document default.
	* opts.c (decode_options): Set max-fields-for-field-sensitive to
	100 for optimize >= 2.

	* gcc.dg/tree-ssa/pta-callused.c: New testcase.

From-SVN: r137453

6 files changed, 87 insertions, 1 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a3c6b76c..9655811 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2008-07-04  Richard Guenther  <rguenther@suse.de>
+
+	* tree-ssa-structalias.c (lookup_vi_for_tree): Declare.
+	(do_sd_constraint): Handle a dereference of ESCAPED and CALLUSED
+	properly to compute the reachability set if we do field-sensitive PTA.
+	* invoke.texi (max-fields-for-field-sensitive): Document default.
+	* opts.c (decode_options): Set max-fields-for-field-sensitive to
+	100 for optimize >= 2.
+
 2008-07-04  Kai Tietz  <kai.tietz@onevision.com>
 
 	* config.gcc (extra_headers): Add cross-stdarg.h for target
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 31d931e..5732d98 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -7323,7 +7323,8 @@ duplicated when threading jumps.
 
 @item max-fields-for-field-sensitive
 Maximum number of fields in a structure we will treat in
-a field sensitive manner during pointer analysis.
+a field sensitive manner during pointer analysis.  The default is zero
+for -O0, and -O1 and 100 for -Os, -O2, and -O3.
 
 @item prefetch-latency
 Estimate on average number of instructions that are executed before
diff --git a/gcc/opts.c b/gcc/opts.c
index 0bea9e4..c26260a 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -903,6 +903,9 @@ decode_options (unsigned int argc, const char **argv)
 
       /* Allow more virtual operators to increase alias precision.  */
       set_param_value ("max-aliased-vops", 500);
+
+      /* Track fields in field-sensitive alias analysis.  */
+      set_param_value ("max-fields-for-field-sensitive", 100);
     }
 
   if (optimize >= 3)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ef05b67..923bd13 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2008-07-04  Richard Guenther  <rguenther@suse.de>
+
+	* gcc.dg/tree-ssa/pta-callused.c: New testcase.
+
 2008-07-04  Kai Tietz  <kai.tietz@onevision.com>
 
 	* gcc.dg/callabi/callabi.h: New.
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pta-callused.c b/gcc/testsuite/gcc.dg/tree-ssa/pta-callused.c
new file mode 100644
index 0000000..44d095a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pta-callused.c
@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 --param max-fields-for-field-sensitive=2 -fdump-tree-alias" } */
+
+struct Foo {
+  int *p, *q;
+};
+
+int foo (int ***x) __attribute__((pure));
+
+int bar (int b)
+{
+  int i;
+  struct Foo f;
+  int *p, **q;
+  p = &i;
+  f.p = &i;
+  f.q = f.p;
+  if (b)
+    q = &f.p;
+  else
+    q = &f.q;
+  return foo (&q);
+}
+
+/* { dg-final { scan-tree-dump "CALLUSED = { f f.q i q }" "alias" } } */
+/* { dg-final { cleanup-tree-dump "alias" } } */
+
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 5531256..0b68b84 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -262,6 +262,7 @@ struct variable_info
 typedef struct variable_info *varinfo_t;
 
 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
+static varinfo_t lookup_vi_for_tree (tree);
 
 /* Pool of variable info structures.  */
 static alloc_pool variable_info_pool;
@@ -1406,6 +1407,47 @@ do_sd_constraint (constraint_graph_t graph, constraint_t c,
       goto done;
     }
 
+  /* For x = *ESCAPED and x = *CALLUSED we want to compute the
+     reachability set of the rhs var.  As a pointer to a sub-field
+     of a variable can also reach all other fields of the variable
+     we simply have to expand the solution to contain all sub-fields
+     if one sub-field is contained.  */
+  if (c->rhs.var == escaped_id
+      || c->rhs.var == callused_id)
+    {
+      bitmap vars = NULL;
+      /* In a first pass record all variables we need to add all
+         sub-fields off.  This avoids quadratic behavior.  */
+      EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
+	{
+	  varinfo_t v = lookup_vi_for_tree (get_varinfo (j)->decl);
+	  if (v->next != NULL)
+	    {
+	      if (vars == NULL)
+		vars = BITMAP_ALLOC (NULL);
+	      bitmap_set_bit (vars, v->id);
+	    }
+	}
+      /* In the second pass now do the addition to the solution and
+         to speed up solving add it to the delta as well.  */
+      if (vars != NULL)
+	{
+	  EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
+	    {
+	      varinfo_t v = get_varinfo (j);
+	      for (; v != NULL; v = v->next)
+		{
+		  if (bitmap_set_bit (sol, v->id))
+		    {
+		      flag = true;
+		      bitmap_set_bit (delta, v->id);
+		    }
+		}
+	    }
+	  BITMAP_FREE (vars);
+	}
+    }
+
   /* For each variable j in delta (Sol(y)), add
      an edge in the graph from j to x, and union Sol(j) into Sol(x).  */
   EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)