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Re: [rfc cpp] extra checking for build(...)
- From: "Zack Weinberg" <zack at codesourcery dot com>
- To: Richard Henderson <rth at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Tue, 17 Feb 2004 13:10:51 -0800
- Subject: Re: [rfc cpp] extra checking for build(...)
- References: <20040215104021.GA23400@redhat.com>
Richard Henderson <firstname.lastname@example.org> writes:
> For tree-ssa, I need to add an extra operand to CALL_EXPR. This
> means updating all places that we build CALL_EXPRs. I think I
> got them all, but the last one took quite a while to locate.
> I was thinking that something like this would make it easier to
> track this sort of thing down. In time we could transition to
> the buildN functions, much like we've done with gen_rtx_fmt_ee,
> but that's more churn than I'm willing to get myself into all at
> Is there a good way to get the preprocessor not to bitch about
> the use of a gcc extension here? #pragma extensions on/off?
A cheesy way would be: put it at the very end of tree.h and precede
with #pragma GCC system_header. We have no other way of doing that,
although I would have no objection to adding
#pragma GCC preprocessor_extensions on/off
It occurs to me that _buildC2 would be simpler if one could write
"rest ## , blah blah" and have the comma deleted - this feature
doesn't exist but only because Neil and I couldn't think of a use for
it, and now here it is. So if you went and implemented that, then
you'd be restricted to GCC >=3.5 anyway, and there would be no reason
not to do the new #pragma.
> I'll note that I don't know how to write this construct with
> c99 __VA_ARGS__, since (1) apparently c99 requires __VA_ARGS__
> to be *used*
... news to me ...
> and (2) I don't think you can handle zero arguments.
No, you can't. I filed a DR about this but haven't heard anything.