identifying c++ aliasing violations

[Richard Guenther]

On 12/4/05, Jack Howarth <howarth@bromo.msbb.uc.edu> wrote:
>     In compiling xplor-nih under gcc 4.1 (it is a mix of c, c++ and fortran)
> I discovered one of its c++ source files causes segfaults at optimization
> levels higher than -O1 unless I add -fno-strict-aliasing to the compile
> flags. In that case, there program passes all of its testsuite without
> any segfaults. Unfortunately, the offending source file, dint-node.cc,
> doesn't result in any warnings with  -Wstrict-aliasing.
>      Is there any documentation on how to debug aliasing rule violations
> in such cases where g++ is unable to produce any warnings? Are there any
> tutorials or documentation on how to debug such situations? Thanks in
> advance for any advice.

4.1 and previous releases do not warn for aliasing issues in C++.  Try
recent 4.2 snapshots, which have this capability.

Maybe we can backport the warning to 4.1.

Richard.