gimple-isel: Recognize vec_extract pattern.

In gimple-isel we already deduce a vec_set pattern from an
ARRAY_REF(VIEW_CONVERT_EXPR).  This patch does the same for a
vec_extract.

The code is largely similar to the vec_set one
including the addition of a can_vec_extract_var_idx_p function
in optabs.cc to check if the backend can handle a register
operand as index.  We already have can_vec_extract in
optabs-query but that one checks whether we can extract
specific modes.

With the introduction of an internal function for vec_extract
the expander must not FAIL.  For vec_set this has already been
the case so adjust the documentation accordingly.

Additionally, clarify the wording of the vector-vector case for
vec_extract.

gcc/ChangeLog:

	* doc/md.texi: Document that vec_set and vec_extract must not
	fail.
	* gimple-isel.cc (gimple_expand_vec_set_expr): Rename this...
	(gimple_expand_vec_set_extract_expr): ...to this.
	(gimple_expand_vec_exprs): Call renamed function.
	* internal-fn.cc (vec_extract_direct): Add.
	(expand_vec_extract_optab_fn): New function to expand
	vec_extract optab.
	(direct_vec_extract_optab_supported_p): Add.
	* internal-fn.def (VEC_EXTRACT): Add.
	* optabs.cc (can_vec_extract_var_idx_p): New function.
	* optabs.h (can_vec_extract_var_idx_p): Declare.

0 files changed, 0 insertions, 0 deletions