2006-12-21  Nathan Sidwell  <nathan@codesourcery.com>

	PR target/28966
	PR target/29248
	* reload1.c (reload): Realign stack after it changes size.

	* gcc.dg/rs6000-leaf.c: New.

--- gcc/reload1.c	(revision 120101)
+++ gcc/reload1.c	(revision 120102)
@@ -888,16 +888,8 @@ reload (rtx first, int global)
     {
       int something_changed;
       int did_spill;
-
       HOST_WIDE_INT starting_frame_size;
 
-      /* Round size of stack frame to stack_alignment_needed.  This must be done
-	 here because the stack size may be a part of the offset computation
-	 for register elimination, and there might have been new stack slots
-	 created in the last iteration of this loop.  */
-      if (cfun->stack_alignment_needed)
-        assign_stack_local (BLKmode, 0, cfun->stack_alignment_needed);
-
       starting_frame_size = get_frame_size ();
 
       set_initial_elim_offsets ();
@@ -964,6 +956,20 @@ reload (rtx first, int global)
       /* If we allocated another stack slot, redo elimination bookkeeping.  */
       if (starting_frame_size != get_frame_size ())
 	continue;
+      if (starting_frame_size && cfun->stack_alignment_needed)
+	{
+	  /* If we have a stack frame, we must align it now.  The
+	     stack size may be a part of the offset computation for
+	     register elimination.  So if this changes the stack size,
+	     then repeat the elimination bookkeeping.  We don't
+	     realign when there is no stack, as that will cause a
+	     stack frame when none is needed should
+	     STARTING_FRAME_OFFSET not be already aligned to
+	     STACK_BOUNDARY.  */
+	  assign_stack_local (BLKmode, 0, cfun->stack_alignment_needed);
+	  if (starting_frame_size != get_frame_size ())
+	    continue;
+	}
 
       if (caller_save_needed)
 	{
--- gcc/testsuite/gcc.dg/rs6000-leaf.c	(revision 0)
+++ gcc/testsuite/gcc.dg/rs6000-leaf.c	(revision 120102)
@@ -0,0 +1,8 @@
+/* { dg-do compile { target rs6000-*-* } }  */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler-not "\tstwu 1,-\[0-9\]*(1)\n" } } */
+
+int Leaf (int i)
+{
+  return i + 1;
+}