[Bug rtl-optimization/89721] __builtin_mffs sometimes optimized away

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89721

--- Comment #7 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Author: segher
Date: Thu Oct 17 19:52:55 2019
New Revision: 277132

URL: https://gcc.gnu.org/viewcvs?rev=277132&root=gcc&view=rev
Log:
        Backport from trunk
        2019-03-15  Segher Boessenkool  <seg...@kernel.crashing.org>

        PR rtl-optimization/89721
        * lra-constraints (invariant_p): Return false if side_effects_p holds.

Modified:
    branches/gcc-7-branch/gcc/ChangeLog
    branches/gcc-7-branch/gcc/lra-constraints.c