pr 22207: Spurious 'might be used uninitialized' warnings

[Ian Lance Taylor]

Brian Dessent <brian@dessent.net> writes:

> I hope it's not bad etiquette to ping a PR but I would greatly
> appreciate it if someone could take a quick look at PR 22207 which has
> gone for several months with no replies.
> 
> The problem involves bogus "might be used uninitialized" warnings in STL
> headers, but only at -O2 and above.  This makes building with "-Wall
> -Werror" impossible without having to disable some warnings.
> 
> The problem occurs with gcc 3.4.4 and is a regression from 3.3.3, which
> worked fine.  The PR includes a testcase that reproduces it under Cygwin
> but not Linux, so it very well may be something that is
> Cygwin-specific.  If you need any further information please let me
> know.

I took a look at this PR.  I don't see any immediate fix.  The
exception handling code is introducing branches in which the values
are used without being initialized.  Since this doesn't happen for
GNU/Linux, I would guess that this is related to the setjmp/longjmp
exceptions which are used on Cygwin.  But I don't know for sure.

Since this test case works in the current sources, and since it is
only a warning which can be turned off using -Wno-uninitialized, I'm
not going to look at it further.  Sorry.

Ian