[Bug tree-optimization/86034] [9 regression] wrong code for bit-field manipulation at -Os

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86034

--- Comment #4 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
Author: ebotcazou
Date: Sun Jun  3 11:51:10 2018
New Revision: 261128

URL: https://gcc.gnu.org/viewcvs?rev=261128&root=gcc&view=rev
Log:
        PR tree-optimization/86034
        * gimple-ssa-store-merging.c (output_merged_store): Convert the RHS to
        the unsigned bitfield type in a bit insertion sequence if it does not
        have a larger precision than the bitfield size.
        (process_store): Also bypass widening conversions for BIT_INSERT_EXPR.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr86034.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimple-ssa-store-merging.c
    trunk/gcc/testsuite/ChangeLog