re PR tree-optimization/39358 (Wrong aliasing warning with lists)

2009-03-04  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/39358
	* tree-ssa-structalias.c (do_sd_constraint): Fix check for
	escaped_id and callused_id.
	(solve_graph): Likewise.

	* g++.dg/warn/Wstrict-aliasing-bogus-escape-2.C: New testcase.
	* g++.dg/warn/Wstrict-aliasing-bogus-escape-3.C: Likewise.

From-SVN: r144602

5 files changed, 75 insertions, 7 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6eb37db..b75d2dd 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,12 @@
 2009-03-04  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/39358
+	* tree-ssa-structalias.c (do_sd_constraint): Fix check for
+	escaped_id and callused_id.
+	(solve_graph): Likewise.
+
+2009-03-04  Richard Guenther  <rguenther@suse.de>
+
 	PR tree-optimization/39339
 	* tree-sra.c (try_instantiate_multiple_fields): Make it
 	no longer ICE on the above.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index fc081f5..508b7e3 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,11 @@
 2009-03-04  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/39358
+	* g++.dg/warn/Wstrict-aliasing-bogus-escape-2.C: New testcase.
+	* g++.dg/warn/Wstrict-aliasing-bogus-escape-3.C: Likewise.
+
+2009-03-04  Richard Guenther  <rguenther@suse.de>
+
 	PR tree-optimization/39339
 	* gcc.c-torture/execute/pr39339.c: New testcase.
 
diff --git a/gcc/testsuite/g++.dg/warn/Wstrict-aliasing-bogus-escape-2.C b/gcc/testsuite/g++.dg/warn/Wstrict-aliasing-bogus-escape-2.C
new file mode 100644
index 0000000..29414e0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wstrict-aliasing-bogus-escape-2.C
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wstrict-aliasing" } */
+
+#include<list>
+
+struct A
+{
+  virtual ~A();
+};
+
+A* foo();
+
+void bar(std::list<int> x)
+{
+  std::list<int> y = x;
+  if (*y.rbegin())
+    delete foo();
+}
+
diff --git a/gcc/testsuite/g++.dg/warn/Wstrict-aliasing-bogus-escape-3.C b/gcc/testsuite/g++.dg/warn/Wstrict-aliasing-bogus-escape-3.C
new file mode 100644
index 0000000..de6b2c4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wstrict-aliasing-bogus-escape-3.C
@@ -0,0 +1,35 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wstrict-aliasing" } */
+
+struct Node_base {};
+
+struct Node : Node_base
+{
+  int data;
+};
+
+struct List
+{
+  Node_base node, *prev;
+
+  List() : prev(&node) { xyz(); }
+
+  void xyz();
+
+  int back() { return static_cast<Node*>(prev)->data; }
+};
+
+struct A
+{
+  virtual ~A();
+};
+
+A* foo();
+
+void bar()
+{
+  List y;
+  if (y.back())
+    delete foo();
+}
+
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 07fd9ed..732bc6f 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -1524,8 +1524,8 @@ do_sd_constraint (constraint_graph_t graph, constraint_t c,
      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)
+  if (c->rhs.var == find (escaped_id)
+      || c->rhs.var == find (callused_id))
     {
       bitmap vars = NULL;
       /* In a first pass record all variables we need to add all
@@ -1594,9 +1594,10 @@ do_sd_constraint (constraint_graph_t graph, constraint_t c,
 	  /* Merging the solution from ESCAPED needlessly increases
 	     the set.  Use ESCAPED as representative instead.
 	     Same for CALLUSED.  */
-	  else if (get_varinfo (t)->id == escaped_id
-		   || get_varinfo (t)->id == callused_id)
-	    flag |= bitmap_set_bit (sol, get_varinfo (t)->id);
+	  else if (get_varinfo (t)->id == find (escaped_id))
+	    flag |= bitmap_set_bit (sol, escaped_id);
+	  else if (get_varinfo (t)->id == find (callused_id))
+	    flag |= bitmap_set_bit (sol, callused_id);
 	  else if (add_graph_edge (graph, lhs, t))
 	    flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
 	}
@@ -2516,8 +2517,8 @@ solve_graph (constraint_graph_t graph)
 
 	      if (!solution_empty
 		  /* Do not propagate the ESCAPED/CALLUSED solutions.  */
-		  && i != escaped_id
-		  && i != callused_id)
+		  && i != find (escaped_id)
+		  && i != find (callused_id))
 		{
 		  bitmap_iterator bi;