alloca and the difference between required and optimal alignment

Hi all,
at the moment SYSV ABI on i386 and use of double force stack
realignments. This is an unfortunate side effect of double requesting 8
Bytes alignment, even though i387 support requires only 32bit alignment.
Are there other cases like that around? I can think of a number of cases
where it makes sense to align strings to 32bit at least.