re PR middle-end/38503 (warnings from -isystem headers strikes back.)

2009-01-27  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/38503
	* cfgexpand.c (expand_gimple_basic_block): Ignore
	GIMPLE_CHANGE_DYNAMIC_TYPE during expansion.
	* tree-ssa-structalias.c (set_uids_in_ptset): Do not prune
	variables that cannot have TBAA applied.
	(compute_points_to_sets): Do not remove GIMPLE_CHANGE_DYNAMIC_TYPE
	statements.

	* g++.dg/warn/Wstrict-aliasing-bogus-placement-new.C: New testcase.

From-SVN: r143700

5 files changed, 49 insertions, 15 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d2c1f4b..39f89ec 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2009-01-27  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/38503
+	* cfgexpand.c (expand_gimple_basic_block): Ignore
+	GIMPLE_CHANGE_DYNAMIC_TYPE during expansion.
+	* tree-ssa-structalias.c (set_uids_in_ptset): Do not prune
+	variables that cannot have TBAA applied.
+	(compute_points_to_sets): Do not remove GIMPLE_CHANGE_DYNAMIC_TYPE
+	statements.
+
 2009-01-27 Uros Bizjak <ubizjak@gmail.com>
 
 	PR middle-end/38969
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index 6d7fe77..a9a52c4 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -1970,7 +1970,7 @@ expand_gimple_basic_block (basic_block bb)
 		    return new_bb;
 		}
 	    }
-	  else
+	  else if (gimple_code (stmt) != GIMPLE_CHANGE_DYNAMIC_TYPE)
 	    {
 	      tree stmt_tree = gimple_to_tree (stmt);
 	      last = get_last_insn ();
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9b9f8ed..1ebe503 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2009-01-27  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/38503
+	* g++.dg/warn/Wstrict-aliasing-bogus-placement-new.C: New testcase.
+
 2009-01-27 Uros Bizjak <ubizjak@gmail.com>
 
 	PR middle-end/38969
diff --git a/gcc/testsuite/g++.dg/warn/Wstrict-aliasing-bogus-placement-new.C b/gcc/testsuite/g++.dg/warn/Wstrict-aliasing-bogus-placement-new.C
new file mode 100644
index 0000000..514957b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wstrict-aliasing-bogus-placement-new.C
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wstrict-aliasing" } */
+
+inline void *operator new (__SIZE_TYPE__, void *__p) throw() { return __p; }
+
+struct Y {
+  Y() {}
+  int i;
+};
+
+struct X {
+  X() {}
+  void construct(const Y& y)
+  {
+    new (&m_data[0]) Y(y);
+  }
+  bool initialized;
+  char m_data[sizeof (Y)];
+};
+
+void bar(const X&);
+void foo(Y& y)
+{
+  X x;
+  x.construct(y);
+  x.initialized = true;
+  bar(x);
+}
+
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 8b49556b..cae478a 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -4703,7 +4703,8 @@ set_uids_in_ptset (tree ptr, bitmap into, bitmap from, bool is_derefed,
 	     type-based pruning disabled.  */
 	  if (vi->is_artificial_var
 	      || !is_derefed
-	      || no_tbaa_pruning)
+	      || no_tbaa_pruning
+	      || vi->no_tbaa_pruning)
 	    bitmap_set_bit (into, DECL_UID (vi->decl));
 	  else
 	    {
@@ -5496,19 +5497,8 @@ compute_points_to_sets (void)
 	    find_func_aliases (phi);
 	}
 
-      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
-	{
-	  gimple stmt = gsi_stmt (gsi);
-
-	  find_func_aliases (stmt);
-
-	  /* The information in GIMPLE_CHANGE_DYNAMIC_TYPE statements
-	     has now been captured, and we can remove them.  */
-	  if (gimple_code (stmt) == GIMPLE_CHANGE_DYNAMIC_TYPE)
-	    gsi_remove (&gsi, true);
-	  else
-	    gsi_next (&gsi);
-	}
+      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	find_func_aliases (gsi_stmt (gsi));
     }