re PR middle-end/46894 (vector tests fail on powerpc 32-bit)

	PR middle-end/46894
	* explow.c (allocate_dynamic_stack_space): Do not assume more than
	BITS_PER_UNIT alignment if STACK_DYNAMIC_OFFSET or STACK_POINTER_OFFSET
	are defined.

From-SVN: r168968

gcc/ChangeLog

+2011-01-18  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR middle-end/46894
+	* explow.c (allocate_dynamic_stack_space): Do not assume more than
+	BITS_PER_UNIT alignment if STACK_DYNAMIC_OFFSET or STACK_POINTER_OFFSET
+	are defined.
+
 2011-01-18  Ulrich Weigand  <Ulrich.Weigand@de.ibm.com>
 
 	PR tree-optimization/47179

gcc/explow.c

@@ -1148,6 +1148,7 @@ allocate_dynamic_stack_space (rtx size, unsigned size_align,
 {
   HOST_WIDE_INT stack_usage_size = -1;
   rtx final_label, final_target, target;
+  unsigned extra_align = 0;
   bool must_align;
 
   /* If we're asking for zero bytes, it doesn't matter what we point
@@ -1231,21 +1232,25 @@ allocate_dynamic_stack_space (rtx size, unsigned size_align,
      that might result from the alignment operation.  */
 
   must_align = (crtl->preferred_stack_boundary < required_align);
-#if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
-  must_align = true;
-#endif
-
   if (must_align)
     {
-      unsigned extra, extra_align;
-
       if (required_align > PREFERRED_STACK_BOUNDARY)
 	extra_align = PREFERRED_STACK_BOUNDARY;
       else if (required_align > STACK_BOUNDARY)
 	extra_align = STACK_BOUNDARY;
       else
 	extra_align = BITS_PER_UNIT;
-      extra = (required_align - extra_align) / BITS_PER_UNIT;
+    }
+
+  /* ??? STACK_POINTER_OFFSET is always defined now.  */
+#if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
+  must_align = true;
+  extra_align = BITS_PER_UNIT;
+#endif
+
+  if (must_align)
+    {
+      unsigned extra = (required_align - extra_align) / BITS_PER_UNIT;
 
       size = plus_constant (size, extra);
       size = force_operand (size, NULL_RTX);