re PR c++/23337 (ICE initializing array of vectors in C++)

./	PR c++/23337
	* gimplify.c (gimplify_init_ctor_eval): If we see an element of
	vector type, don't try to construct it element by element.  Add an
	assertion that we use a FIELD_DECL when building a COMPONENT_REF.
testsuite/
	PR c++/23337
	* g++.dg/ext/vector2.C: New.

From-SVN: r103177