[Bug tree-optimization/80631] [6/7/8 Regression] Compiling with -O3 -mavx2 gives wrong code

["jakub at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80631

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Tue Dec 12 08:55:02 2017
New Revision: 255574

URL: https://gcc.gnu.org/viewcvs?rev=255574&root=gcc&view=rev
Log:
        PR tree-optimization/80631
        * tree-vect-loop.c (get_initial_def_for_reduction): Fix comment typo.
        (vect_create_epilog_for_reduction): Add INDUC_VAL and INDUC_CODE
        arguments, for INTEGER_INDUC_COND_REDUCTION use INDUC_VAL instead of
        hardcoding zero as the value if COND_EXPR is never true.  For
        INTEGER_INDUC_COND_REDUCTION don't emit the final COND_EXPR if
        INDUC_VAL is equal to INITIAL_DEF, and use INDUC_CODE instead of
        hardcoding MAX_EXPR as the reduction operation.
        (is_nonwrapping_integer_induction): Allow negative step.
        (vectorizable_reduction): Compute INDUC_VAL and INDUC_CODE for
        vect_create_epilog_for_reduction, if no value is suitable, don't
        use INTEGER_INDUC_COND_REDUCTION for now.  Formatting fixes.

        * gcc.dg/vect/pr80631-1.c: New test.
        * gcc.dg/vect/pr80631-2.c: New test.
        * gcc.dg/vect/pr65947-13.c: Expect integer induc cond reduction
        vectorization.

Added:
    trunk/gcc/testsuite/gcc.dg/vect/pr80631-1.c
    trunk/gcc/testsuite/gcc.dg/vect/pr80631-2.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/vect/pr65947-13.c
    trunk/gcc/tree-vect-loop.c