Merge from Sourcery G++ 4.4:

	2009-05-21  Sandra Loosemore  <sandra@codesourcery.com>

	Merge from Sourcery G++ 4.3:

	2009-04-04  Sandra Loosemore  <sandra@codesourcery.com>

	Issue #5104
	PR tree-optimization/39604

	gcc/testsuite
	* g++.dg/tree-ssa/sink-1.C: New.

	gcc/
	* tree_ssa-sink.c (sink_code_in_bb): Do not sink statements out
	of a lexical block containing variable definitions.

2010-07-09  Sandra Loosemore  <sandra@codesourcery.com>

 	Backport from mainline (originally on Sourcery G++ 4.4):
 
 	2010-07-02  Julian Brown  <julian@codesourcery.com>

=== added file 'gcc/testsuite/g++.dg/tree-ssa/sink-1.C'
--- old/gcc/testsuite/g++.dg/tree-ssa/sink-1.C	1970-01-01 00:00:00 +0000
+++ new/gcc/testsuite/g++.dg/tree-ssa/sink-1.C	2010-07-30 12:14:18 +0000
@@ -0,0 +1,50 @@
+/* { dg-do run } */
+/* { dg-options "-O1" } */
+
+class A {
+ public:
+  A() {}
+  virtual ~A() {}  
+  void * dostuff();
+  
+  virtual int dovirtual() = 0;
+};
+
+
+class B : public A {
+ public:
+  B() {}
+  int dovirtual() { return 0;}
+  virtual ~B() {};
+}; 
+
+class C : public B {
+ public:
+  C() {}
+  virtual ~C() {};
+};
+
+void* A::dostuff()
+{
+  return (void*)dovirtual();
+}
+
+/* tree-ssa-sink was sinking the inlined destructor for STUFF out of
+   the first inner block and into the second one, where it was ending up
+   after the inlined constructor for STUFF2.  This is bad because
+   cfgexpand aliases STUFF and STUFF2 to the same storage at -O1
+   (i.e., without -fstrict-aliasing), with the result that STUFF2's
+   vtable was getting trashed. */
+
+int main() {
+  {
+    B stuff;
+    stuff.dostuff();
+  }
+  {
+    C stuff2;
+    stuff2.dostuff();
+  }
+  return 0;
+}
+

=== modified file 'gcc/tree-ssa-sink.c'
--- old/gcc/tree-ssa-sink.c	2009-11-28 16:21:00 +0000
+++ new/gcc/tree-ssa-sink.c	2010-07-30 12:14:18 +0000
@@ -470,6 +470,47 @@
 	  last = false;
 	  continue;
 	}
+
+      /* We cannot move statements that contain references to block-scope
+	 variables out of that block, as this may lead to incorrect aliasing
+	 when we lay out the stack frame in cfgexpand.c.
+	 In lieu of more sophisticated analysis, be very conservative here
+	 and prohibit moving any statement that references memory out of a
+	 block with variables.  */
+      if (gimple_references_memory_p (stmt))
+	{
+	  tree fromblock = gimple_block (stmt);
+	  while (fromblock
+		 && fromblock != current_function_decl
+		 && !BLOCK_VARS (fromblock))
+	    fromblock = BLOCK_SUPERCONTEXT (fromblock);
+	  if (fromblock && fromblock != current_function_decl)
+	    {
+	      gimple tostmt;
+	      tree toblock;
+
+	      if (gsi_end_p (togsi))
+		tostmt = gimple_seq_last_stmt (gsi_seq (togsi));
+	      else
+		tostmt = gsi_stmt (togsi);
+	      if (tostmt)
+		toblock = gimple_block (tostmt);
+	      else
+		toblock = NULL;
+	      while (toblock
+		     && toblock != current_function_decl
+		     && toblock != fromblock)
+		toblock = BLOCK_SUPERCONTEXT (toblock);
+	      if (!toblock || toblock != fromblock)
+		{
+		  if (!gsi_end_p (gsi))
+		    gsi_prev (&gsi);
+		  last = false;
+		  continue;
+		}
+	    }
+	}
+
       if (dump_file)
 	{
 	  fprintf (dump_file, "Sinking ");