[autovect] [patch] more cleanups

[Dorit Nuzman <DORIT at il dot ibm dot com>]

Mostly documentation typos fixes and some code factoring to avoid code
duplication.

Bootstrapped with vectorization enabled on powerpc-linux, tested on the
vectorizer testcases. Committed to autovec-branch.

dorit

        * genopinit.c (vec_pack_usat_optab): Fixed to vec_pack_ssat_optab.
        * tree-vectorizer.c (supportable_widening_operation): Fix typos.
        * tree-vect-analyze.c (vect_mark_stmts_to_be_vectorized): Fix
        documentation and 80 column overflow.
        * tree.def (VEC_WIDEN_MULT_HI_EXPR): Fix typos in documentation.
        * tree-vect-transform.c (vect_gen_widened_results_half): New
function
        (factored out code from vectorizable_type_promotion).
        (vectorizable_type_promotion): Call vect_gen_widened_results_half
        instead of code that was factored out.
        (vectorizable_reduction): Remove redundant assert. vec_stmt is not
set
        to NULL.
        (vect_transform_stmt): No need to set STMT_VINFO_VEC_STMT after
call to
        vectorizable_reduction.
        (vectorizable_load): Change 'if' to 'else' of previous 'if'.

(See attached file: autovec-cleanup.txt)

Attachment: autovec-cleanup.txt
Description: Text document