altivec cleanups

[David Edelsohn]

2001-12-18  Aldy Hernandez  <aldyh@redhat.com>

	* config.gcc: Add support for --enable-altivec.

	* config/rs6000/altivec.h: New.

	* config/rs6000/linuxaltivec.h (SUBSUBTARGET_OVERRIDE_OPTIONS):
	Define.  Fix typo.

	* config/rs6000/rs6000.c (vrsave_operation): Change unspec to
	unspec_volatile.
	(generate_set_vrsave): Generate the unspec here instead of calling
	an .md pattern.
	(generate_set_vrsave): Use gen_rtvec.
	(rs6000_emit_prologue): Replace call to gen_get_vrsave with
	gen_rtx_SET.

	* config/rs6000/rs6000.md ("*movsi_internal1"): Add constraints
	for setting special registers.
	("*set_vrsave_internal"): Use unspec_volatile.
	("set_vrsave"): Remove.
	("get_vrsave"): Remove.

	* config/rs6000/rs6000.h (REG_CLASS_CONTENTS): Add vrsave to
	SPECIAL_REGS.

This patch is okay to commit.

David