Conference decwet::visual

521.0. "alignment faults with optimized code?" by HYDRA::BRYANT () Fri Jun 06 1997 07:29

Hello,

I'm working with a partner whose application is generating 600,000 alignment
faults per second.  I instructed him how to break on them in the VC++ debugger. 
The breaks occur only when the code is built with /02.  The first exception
occurs in a constructor for a class when a member declared as double is
initialized.  Subsequent exceptions are doing the same thing.

He started playing around and found that if he changes the member to float, the
exception does not occur.  Or if he changes the compiler directive NDEBUG to
_DEBUG, the fault does not occur.  Using the multithreaded debug library rather
than the normal multithreaded library also seems to eliminate the exception.

I asked him to create a small reproducer but he is unable to reproduce this
outside his application.

Can anyone comment on what might be going on?

Thanks.
Pat Bryant
Software Partner Engineering