[PATCH, rs6000] VSX load/store rightmost element operations

[PATCH, rs6000] VSX load/store rightmost element operations

Hi,
  This adds support for the VSX load/store rightmost element operations.
  This includes the instructions lxvrbx, lxvrhx, lxvrwx, lxvrdx,
  stxvrbx, stxvrhx, stxvrwx, stxvrdx; And the builtins
  vec_xl_sext() /* vector load sign extend */
  vec_xl_zext() /* vector load zero extend */
  vec_xst_trunc() /* vector store truncate */.

  Testcase results show that the instructions added with this patch show
  up at low/no optimization (-O0), with a number of those being replaced
  with other load and store instructions at higher optimization levels.
  For consistency I've left the tests at -O0.

  [v2] Refreshed per review comments.  Comments cleaned up, indentation
  corrected.

gcc/ChangeLog:
	* config/rs6000/altivec.h (vec_xl_zext, vec_xl_sext, vec_xst_trunc):
	New defines.
	* config/rs6000/rs6000-builtin.def (BU_P10V_OVERLOAD_X): New builtin
	macro.
	(BU_P10V_AV_X): New builtin macro.
	(se_lxvrhbx, se_lxrbhx, se_lxvrwx, se_lxvrdx): Define internal names
	for load and sign extend vector element.
	(ze_lxvrbx, ze_lxvrhx, ze_lxvrwx, ze_lxvrdx): Define internal names
	for load and zero extend vector element.
	(tr_stxvrbx, tr_stxvrhx, tr_stxvrwx, tr_stxvrdx): Define internal names
	for truncate and store vector element.
	(se_lxvrx, ze_lxvrx, tr_stxvrx): Define internal names for overloaded
	load/store rightmost element.
	* config/rs6000/rs6000-call.c (altivec_builtin_types): Define the
	internal monomorphs P10_BUILTIN_SE_LXVRBX, P10_BUILTIN_SE_LXVRHX,
	P10_BUILTIN_SE_LXVRWX, P10_BUILTIN_SE_LXVRDX,
	P10_BUILTIN_ZE_LXVRBX, P10_BUILTIN_ZE_LXVRHX, P10_BUILTIN_ZE_LXVRWX,
	P10_BUILTIN_ZE_LXVRDX,
	P10_BUILTIN_TR_STXVRBX, P10_BUILTIN_TR_STXVRHX, P10_BUILTIN_TR_STXVRWX,
	P10_BUILTIN_TR_STXVRDX,
	(altivec_expand_lxvr_builtin): New expansion for load element builtins.
	(altivec_expand_stv_builtin): Update to for truncate and store builtins.
	(altivec_expand_builtin): Add clases for load/store rightmost builtins.
	(altivec_init_builtins): Add def_builtin entries for
	__builtin_altivec_se_lxvrbx, __builtin_altivec_se_lxvrhx,
	__builtin_altivec_se_lxvrwx, __builtin_altivec_se_lxvrdx,
	__builtin_altivec_ze_lxvrbx, __builtin_altivec_ze_lxvrhx,
	__builtin_altivec_ze_lxvrwx, __builtin_altivec_ze_lxvrdx,
	__builtin_altivec_tr_stxvrbx, __builtin_altivec_tr_stxvrhx,
	__builtin_altivec_tr_stxvrwx, __builtin_altivec_tr_stxvrdx,
	__builtin_vec_se_lxvrx, __builtin_vec_ze_lxvrx, __builtin_vec_tr_stxvrx.
	* config/rs6000/vsx.md (vsx_lxvr<wd>x, vsx_stxvr<wd>x, vsx_stxvr<wd>x):
	New define_insn entries.
	* doc/extend.texi:  Add documentation for vsx_xl_sext, vsx_xl_zext,
	and vec_xst_trunc.

gcc/testsuite/ChangeLog:
	* gcc.target/powerpc/vsx-load-element-extend-char.c: New test.
	* gcc.target/powerpc/vsx-load-element-extend-int.c: New test.
	* gcc.target/powerpc/vsx-load-element-extend-longlong.c: New test.
	* gcc.target/powerpc/vsx-load-element-extend-short.c: New test.
	* gcc.target/powerpc/vsx-store-element-truncate-char.c: New test.
	* gcc.target/powerpc/vsx-store-element-truncate-int.c: New test.
	* gcc.target/powerpc/vsx-store-element-truncate-longlong.c: New test.
	* gcc.target/powerpc/vsx-store-element-truncate-short.c: New test.