2010-10-21 Basile Starynkevitch <basile@starynkevitch.net>

	MELT branch merged with trunk rev 165748



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/melt-branch@165750 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 27 insertions, 1 deletions

diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 5796ea1f09a..f3663185e68 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -173,6 +173,32 @@ variable_size (tree size)
 /* An array of functions used for self-referential size computation.  */
 static GTY(()) VEC (tree, gc) *size_functions;
 
+/* Look inside EXPR into simple arithmetic operations involving constants.
+   Return the outermost non-arithmetic or non-constant node.  */
+
+static tree
+skip_simple_constant_arithmetic (tree expr)
+{
+  while (true)
+    {
+      if (UNARY_CLASS_P (expr))
+	expr = TREE_OPERAND (expr, 0);
+      else if (BINARY_CLASS_P (expr))
+	{
+	  if (TREE_CONSTANT (TREE_OPERAND (expr, 1)))
+	    expr = TREE_OPERAND (expr, 0);
+	  else if (TREE_CONSTANT (TREE_OPERAND (expr, 0)))
+	    expr = TREE_OPERAND (expr, 1);
+	  else
+	    break;
+	}
+      else
+	break;
+    }
+
+  return expr;
+}
+
 /* Similar to copy_tree_r but do not copy component references involving
    PLACEHOLDER_EXPRs.  These nodes are spotted in find_placeholder_in_expr
    and substituted in substitute_in_expr.  */
@@ -241,7 +267,7 @@ self_referential_size (tree size)
   VEC(tree,gc) *args = NULL;
 
   /* Do not factor out simple operations.  */
-  t = skip_simple_arithmetic (size);
+  t = skip_simple_constant_arithmetic (size);
   if (TREE_CODE (t) == CALL_EXPR)
     return size;