c++/2045: no warning when a non void function falls through without a return value; bad code generated.

[jamie at turbolabs dot com]

>Number:         2045
>Category:       c++
>Synopsis:       no warning when a non void function falls through without a return value; bad code generated.
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Feb 20 18:16:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Jamie Painter
>Release:        gcc version 2.95.2 19991024 (release)
>Organization:
>Environment:
i586-pc-linux
TurboLinux workstaion distribution 6.0
glibc-2.1.2-15, libstdc++-2.10-2
>Description:
A non void function that fails to return a value does not always yield a warning or error message, even with -Wall, using gcc 2.95.2.  The attached example demonstrates this.
It's quite small before running through the preprocessor :-)

Worse, the generated code ends up calling the return value destructor, even though a return value was never constructed.

I also tried this with the current gcc-3_0-branch snapshot via http://www.codesourcery.com/gcc-compile.shtml.  This compiler version gives a warning (as it should), but still generates bad code (deconstructing an object that was never constructed).  Without -Wall, no warning is given, but bad code is generated.
>How-To-Repeat:
g++ -Wall -o t1 t1.cpp
>Fix:
Return a value from the non void function.
>Release-Note:
>Audit-Trail:
>Unformatted:
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