PR c++/17642

	PR c++/17642
	* stor-layout.c (layout_decl): Use fold_convert, not convert.
	(bit_from_pos): Likewise.
	(byte_from_pos): Likewise.
	(pos_from_bit): Likewise.
	(normalize_offset): Likewise.
	(place_field): Likewise.
	(finalize_type_size): Likewise.
	(layout_type): Likewise.
	* tree.c (build_index_type): Likewise.

	PR c++/17642
	* cp-tree.h (fold_if_not_in_template): New function.
	* call.c (build_conditional_expr): Use fold_if_not_in_template.
	(build_cxx_call): Likewise.
	* cvt.c (convert_to_complex): Likewise.
	(ocp_convert): Likewise.
	(convert): Likewise.
	(convert_force): Likewise.
	* decl.c (compute_array_index_type): Clear
	processing_template_decl while folding array bounds.
	* pt.c (convert_nontype_argument): Clear
	processing_template_decl while processing non-type argument
	initialization.
	* tree.c (fold_if_not_in_template): New function.
	* typeck.c (build_class_member_access_expr): Use
	fold_if_not_in_template.
	(build_array_ref): Likewise.
	(build_binary_op): Likewise.  Do not try to optimize computations
	when processing templates.
	(cp_pointer_int_sum): Use fold_if_not_in_template.
	(pointer_diff): Likewise.
	(build_unary_op): Likewise.
	(build_reinterpret_cast): Likewise.
	(get_delta_difference): Likewise.
	(expand_ptrmemfunc_cst): Likewise.
	(dubious_conversion_warnings): Likewise.

	* g++.dg/template/crash23.C: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@88217 138bc75d-0d04-0410-961f-82ee72b054a4