[Bug middle-end/71310] Bitfields cause load hit store with smaller store and larger load

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71310

--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Tue May  9 12:24:53 2017
New Revision: 247789

URL: https://gcc.gnu.org/viewcvs?rev=247789&root=gcc&view=rev
Log:
        PR testsuite/80678
        2016-06-14  Richard Biener  <rguent...@suse.de>

        PR middle-end/71310
        PR bootstrap/71510
        * expr.h (get_bit_range): Declare.
        * expr.c (get_bit_range): Export.
        * fold-const.c (optimize_bit_field_compare): Use get_bit_range and
        word_mode again to constrain the bitfield access.

        2016-06-11  Segher Boessenkool  <seg...@kernel.crashing.org>

        PR middle-end/71310
        * fold-const.c (optimize_bit_field_compare): Don't try to use
        word_mode unconditionally for reading the bit field, look at
        DECL_BIT_FIELD_REPRESENTATIVE instead.

        * gcc.target/powerpc/pr71310.c: New testcase.

Added:
    branches/gcc-6-branch/gcc/testsuite/gcc.target/powerpc/pr71310.c
Modified:
    branches/gcc-6-branch/gcc/ChangeLog
    branches/gcc-6-branch/gcc/expr.c
    branches/gcc-6-branch/gcc/expr.h
    branches/gcc-6-branch/gcc/fold-const.c
    branches/gcc-6-branch/gcc/testsuite/ChangeLog