* fold-const.c (native_encode_expr): New function to encode

	* fold-const.c (native_encode_expr): New function to encode
	the target representation of an INTEGER_CST, REAL_CST, COMPLEX_CST
	or VECTOR_CST into a specified buffer.
	(native_encode_int): New function.
	(native_encode_real): New function.
	(native_encode_complex): New function.
	(native_encode_vector): New function.
	(native_interpret_expr): Inverse of native_encode_expr to convert
	a target representation into an INTEGER_CST, REAL_CST etc...
	(native_interpret_int): New function.
	(native_interpret_real): New function.
	(native_interpret_complex): New function.
	(native_interpret_vector): New function.
	(fold_view_convert_expr): New function to constant fold/evaluate
	a VIEW_CONVERT_EXPR of a suitable constant expression.
	(fold_unary) <VIEW_CONVERT_EXPR>: Call fold_view_convert_expr.
	Change call of build1 to fold_build1 when constructing a
	VIEW_CONVERT_EXPR.

	* gcc.target/i386/20050113-1.c: Tweak testcase to reflect that casts
	of integers to a vector types are now constant expressions in C.
	* gcc.dg/vect/vect-fold-1.c: New test case.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@112927 138bc75d-0d04-0410-961f-82ee72b054a4