[Bug tree-optimization/92412] excessive errno aliasing assumption defeats optimization

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92412

--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> ---
Author: msebor
Date: Tue Nov 12 18:49:31 2019
New Revision: 278099

URL: https://gcc.gnu.org/viewcvs?rev=278099&root=gcc&view=rev
Log:
PR tree-optimization/92412 - excessive errno aliasing assumption defeats
optimization

gcc/ChangeLog:

        PR tree-optimization/92412
        * targhooks.c (default_ref_may_alias_errno): Errono can only alias
        extern variables.

gcc/testsuite/ChangeLog:

        PR tree-optimization/92412
        * gcc.dg/strlenopt-91.c: New test.


Added:
    trunk/gcc/testsuite/gcc.dg/strlenopt-91.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/targhooks.c
    trunk/gcc/testsuite/ChangeLog