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[PATCH] Disallow VECTOR_CSTs with missing elements

The user can happily provide not enough elements for the initializer
of a vector variable which eventually leads to build_vector_from_ctor
constructing a VECTOR_CST with an element count that does not match
TYPE_VECTOR_SUBPARTS.  Not a good thing to have in our IL (and nothing
existing code expects).

Thus I am testing the following (luckily at least the C fronted
doesn't have a way of using designated initializers for vector
elements - otherwise we'd have to care about the index values
in the constructor as well).


2010-07-29  Richard Guenther  <>

	* tree.c (build_vector): Assert that the vector constant
	has enough elements.
	(build_vector_from_ctor): Pad with trailing zeros.

Index: gcc/tree.c
*** gcc/tree.c	(revision 162637)
--- gcc/tree.c	(working copy)
*************** build_vector (tree type, tree vals)
*** 1318,1323 ****
--- 1318,1324 ----
    tree v = make_node (VECTOR_CST);
    int over = 0;
    tree link;
+   unsigned cnt = 0;
    TREE_VECTOR_CST_ELTS (v) = vals;
    TREE_TYPE (v) = type;
*************** build_vector (tree type, tree vals)
*** 1326,1331 ****
--- 1327,1333 ----
    for (link = vals; link; link = TREE_CHAIN (link))
        tree value = TREE_VALUE (link);
+       cnt++;
        /* Don't crash if we get an address constant.  */
        if (!CONSTANT_CLASS_P (value))
*************** build_vector (tree type, tree vals)
*** 1334,1339 ****
--- 1336,1343 ----
        over |= TREE_OVERFLOW (value);
+   gcc_assert (cnt == TYPE_VECTOR_SUBPARTS (type));
    TREE_OVERFLOW (v) = over;
    return v;
*************** build_vector_from_ctor (tree type, VEC(c
*** 1350,1355 ****
--- 1354,1362 ----
    FOR_EACH_CONSTRUCTOR_VALUE (v, idx, value)
      list = tree_cons (NULL_TREE, value, list);
+   for (; idx < TYPE_VECTOR_SUBPARTS (type); ++idx)
+     list = tree_cons (NULL_TREE,
+ 		      fold_convert (TREE_TYPE (type), integer_zero_node), list);
    return build_vector (type, nreverse (list));

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