[Bug tree-optimization/103176] -foptimize-strlen causes stringop-overflow warning

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103176

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2021-11-10
     Ever confirmed|0                           |1
                 CC|                            |msebor at gcc dot gnu.org

--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> ---
Historically, flow-dependent warnings in GCC have relied on optimization.  Some
work without it and just yield better results with it (e.g., -Wuninitialized),
others require it and won't do anything otherwise (e.g., -Warray-bounds).  This
is starting to change so that more warnings are useful even without
optimization, but only slowly, and to a limited extent (e.g., to see across
function call boundaries requires inlining and likely will for the foreseeable
future).  Some warnings like -Wstringop-overflow are a hybrid: some instances
are issued only during the strlen optimization, others at other times.  None of
these warnings are free of false positives (in fact, none ever are).  Some are
unavoidable due to limits inherent in computing, some due to design trade-offs,
others are incidental (i.e., bugs).  To tell where the instances in comment #0
fall we ask for a test case, or at least the translation unit, so that we can
easily reproduce and analyze them (see https://gcc.gnu.org/bugs/).  I set the
status to WAITING until you have provided one.