install.texi: Add documentation for --enable-altivec.

install.texi: Add documentation for --enable-altivec.

2001-12-19  Aldy Hernandez  <aldyh@redhat.com>

        * doc/install.texi: Add documentation for --enable-altivec.

        * 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.

From-SVN: r48194