[Bug middle-end/79374] missing sometimes-uninitialized warning in switch statement

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79374

Jeffrey A. Law <law at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |law at redhat dot com
         Resolution|---                         |DUPLICATE

--- Comment #2 from Jeffrey A. Law <law at redhat dot com> ---
To be more precise, conditional constant propagation optimistically ignores PHI
arguments associated with undefined values.  That makes the PHI to select a
value of "rv" at the merge point before the return statement a degenerate with
the value 0.

At that point the path associated with the undefined value gets removed from
the CFG and thus there's no warning later.

GCC and Clang have significantly different philosophical approaches to
uninitialized warnings and as a result they do not always agree on when to
warn.

*** This bug has been marked as a duplicate of bug 44042 ***