Re: Argument passing conventions and optimization

pradeep tumati <ptumati@yahoo.com> writes:


>Now, assuming that we are using GCC 3.2.x (x86, linux) does the
>following situation ever arise?
>
>Do we ever get a situation where one of the GCC optimizations changes
>the argument passing mechanism?


In GCC 3.2.x, the -O* and -f* options will not change the argument
passing mechanism. Some other options, e.g. `-mrtd' and
`-mregparm-N', do change it.


In future versions of GCC, this is likely to change. For example,
argument passing conventions for static functions whose address is not
taken will use different (more efficient) calling conventions.


Our moderator replied:


>[Other than inlining, I don't recall ever seeing an optimization that
>affected the calling sequence.


There are others, e.g. tail call and sibling call optimization.
However, although they affect the calling sequence, they do not affect
the argument passing mechanism.
--
Fergus Henderson <fjh@cs.mu.oz.au> | "I have always known that the pursuit
The University of Melbourne | of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh> | -- the last words of T. S. Garp.

Return to the comp.compilers page.
Search the comp.compilers archives again.