gimplify.c (gimplify_modify_expr_to_memset): Assert our documented assumptions.

2008-06-26  Olivier Hainque  <hainque@adacore.com>

	gcc/
	* gimplify.c (gimplify_modify_expr_to_memset): Assert our
	documented assumptions.

	testsuite/
	* gnat.dg/aligned_vla.adb: New test.

From-SVN: r137171

gcc/ChangeLog

+2008-06-26  Olivier Hainque  <hainque@adacore.com>
+
+	* gimplify.c (gimplify_modify_expr_to_memset): Assert our
+	documented assumptions.
+
 2008-06-26  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* dwarf2out.c: Remove trailing white spaces.  Break long line

gcc/gimplify.c

@@ -2809,8 +2809,19 @@ gimplify_modify_expr_to_memcpy (tree *expr_p, tree size, bool want_value)
 static enum gimplify_status
 gimplify_modify_expr_to_memset (tree *expr_p, tree size, bool want_value)
 {
-  tree t, to, to_ptr;
+  tree t, from, to, to_ptr;
 
+  /* Assert our assumptions, to abort instead of producing wrong code
+     silently if they are not met.  Beware that the RHS CONSTRUCTOR might
+     not be immediately exposed.  */
+  from = GENERIC_TREE_OPERAND (*expr_p, 1);  
+  if (TREE_CODE (from) == WITH_SIZE_EXPR)
+    from = TREE_OPERAND (from, 0);
+
+  gcc_assert (TREE_CODE (from) == CONSTRUCTOR
+	      && VEC_empty (constructor_elt, CONSTRUCTOR_ELTS (from)));
+
+  /* Now proceed.  */
   to = GENERIC_TREE_OPERAND (*expr_p, 0);
 
   to_ptr = build_fold_addr_expr (to);

gcc/testsuite/ChangeLog

+2008-06-27  Olivier Hainque  <hainque@adacore.com>
+
+	* gnat.dg/aligned_vla.adb: New test.
+
 2008-06-26  Joseph Myers  <joseph@codesourcery.com>
 
 	* gcc.dg/inline-32.c, gcc.dg/inline-32a.c: New tests.

gcc/testsuite/gnat.dg/aligned_vla.adb

+--  { dg-do run }
+
+procedure Aligned_Vla is
+
+   type Table is array (Integer range <>) of Integer;
+   for Table'Alignment use Long_Float'Alignment;
+
+   K : constant := 1;
+   Konstants : Table (1 .. 4) := (others => K);
+
+   procedure Check_Copy (Len : Integer) is
+      My_Konstants : Table (1 .. Len) := Konstants (1 .. 1 + Len - 1);
+   begin
+      for I in My_Konstants'Range loop
+         if My_Konstants (I) /= K then
+            raise Program_Error;
+         end if;
+      end loop;
+   end;
+
+begin
+   Check_Copy (Len => 4);
+end;