Re: GCC's statement expression extension

[Linus Torvalds <torvalds at transmeta dot com>]

In article <20000727192618Z.mitchell@codesourcery.com>,
Mark Mitchell  <mark@codesourcery.com> wrote:
>
>I'm much more sympathetic to preserving brokenness in the compiler to
>benefit a popular program that users need (like the Linux kernel) than
>the SPEC, which is only used by the community to evaluate the
>compiler.

Note that the Linux kernel is not adevrse to change - I've disagreed
about some things in the past, but they have not been because the kernel
cannot change to accomodate a better compiler, but because I've
disagreed with the definition of "better" ;)

I do not actually think that the kernel is the "major" user of the
statement expression - I suspect there are many other users that may
even be completely unaware of this whole discussion.  But assuming the
kernel _was_ one of the major users, I would still encourage the gcc
maintainers to break existing functionality if it results in a better
compiler.

I may complain if I think things are DEproving (ie I'd really think that
removing the statement expression would be a bad thing), but please
don't "preserve brokenness in the compiler" due to the Linux kernel. 
I'd hate to feel that the Linux kernel was seen as an impediment for a
better compiler.  Really.  That would be the _last_ thing I'd want to
happen. 

If making syntactic or other changes to expression statements is
required for a better compiler, I'd be all for it.  Please don't
hesitate at all to add a requirement that "return" be used inside
statement expressions, for example.  At least not on account of Linux. 

We can easily change things like that - but having to rely on a less
powerful language would be painful. 

		Linus