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Re: Builtin: stack pointer
- From: Renato Golin <renato dot golin at linaro dot org>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: gcc <gcc at gcc dot gnu dot org>, Behan Webster <behanw at converseincode dot com>, Mark Charlebois <mcharleb at quicinc dot com>
- Date: Thu, 27 Mar 2014 11:50:40 +0000
- Subject: Re: Builtin: stack pointer
- Authentication-results: sourceware.org; auth=none
- References: <CAMSE1kc3FJOq+mh=AD-FQhrGW+aVpVkWFdhfHCM+c=ZgN6Kpug at mail dot gmail dot com> <20140327104412 dot GT1817 at tucnak dot redhat dot com> <CAMSE1kfGRQ08kFJQSsmCFgwfNEfxx_GRVSh5CvgMLiC85_vHpA at mail dot gmail dot com> <20140327113318 dot GW1817 at tucnak dot redhat dot com>
On 27 March 2014 11:33, Jakub Jelinek <jakub@redhat.com> wrote:
> Sure, normally register keyword is just a hint, that e.g. GCC I think
> ignores whenever optimizing (for -O0 it means a variable doesn't have to
> be allocated on the stack), but when it is part of the GNU global/local register
> variable extension (i.e. there is both register keyword and
> asm ("<registername>"), then register is not a mere hint, but a requirement.
Yes, I know. That's why I said it was a "joint issue" of that AND the
IR problem. The extension syntax is clear and precise.
> E.g. glibc uses such inline asms for inline syscalls heavily, other projects
> similarly.
Good to know. I had plans of compiling glibc with LLVM soon, and this
might just be another strong point towards implementing named
registers in LLVM.
Thanks,
--renato