[autovect] [patch] detect mult-hi and sad patterns

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

This patch detects the sum-of-absolute-differences idiom and the
multiply-highpart idiom, for targets that have specialized vector support
for these idioms.
On targets that don't directly support the multiply-highpart, it can be
vectorized using widening-multiplication (or data-unpacking and regular
multiplication), followed by shift and data-packing (for the final
truncate).
On targets that don't directly support the sum-of-absolute-differences
(sad) idiom, it can be vectorized using subtract, abs, and
widening-summation. The expansion of sad was not tested because I don't
have it modelled on any target yet. Bootstrapped with vectorization enabled
and tested on the vectorizer testcases on powerpc-linux.

dorit

Changelog:

+       * expr.c (expand_expr_real_1): Implement MULT_HI_EXPR case.
+       * genopinit.c (sad_optab): Initialize new optab.
+       * optabs.c (optab_for_tree_code): Add case for SAD_EXPR.
+       (sad_optab): Initialize new optab.
+       * optabs.h (OTI_sad): New optan index.
+       (sad_optan): New optab.
+       * tree-inline.c (estimate_num_insns_1): Add case for SAD_EXPR.
+       * tree-pretty-print.c (dump_generic_node): Add case for SAD_EXPR.
+       (op_prio): Add case for SAD_EXPR.
+       * tree-vect-analyze.c (vect_recog_sad_pattern): New function.
+       (vect_recog_mult_hi_pattern): Implement.
+       (vect_recog_dot_prod_pattern, vect_recog_widen_mult_pattern):
+       (vect_recog_widen_sum_pattern, vect_recog_unsigned_subsat_pattern):
+       (vect_pattern_recog_1): Replace build with appropriate buildN.
+       * tree-vect-transform.c (get_initial_def_for_reduction): Add case
for
+       SAD_EXPR.
+       * tree-vectorizer.h (NUM_PATTERNS): Set to 6.
+       (vect_recog_sad_pattern): New function declaration.
+       * tree.def (SAD_EXPR): New tree-code.
+

(See attached file: patch.oct23.txt)

Attachment: patch.oct23.txt
Description: Text document