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Re: Proposed doc update for Explicit Reg Vars 3/3
- From: Jeff Law <law at redhat dot com>
- To: David Wohlferd <dw at LimeGreenSocks dot com>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
- Cc: Segher Boessenkool <segher at kernel dot crashing dot org>, Sandra Loosemore <sandra at codesourcery dot com>
- Date: Mon, 19 Oct 2015 23:22:06 -0600
- Subject: Re: Proposed doc update for Explicit Reg Vars 3/3
- Authentication-results: sourceware.org; auth=none
- References: <561C3DAE dot 8050505 at LimeGreenSocks dot com>
On 10/12/2015 05:09 PM, David Wohlferd wrote:
Like with the global register variables, please consider going processor
agnostic here and using r<N> for some value of N rather than using
severely dated m68k examples.
Patch 3/3 is the update for the Local Register Variables page (attached).
This patch starts with a question. Looking at bug
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64951 (register variable
with template function) is this a bug that will be fixed? Or a
limitation that should be doc'ed? Both the current docs and the patch
ignore this bug.
As with patch #2, this is primarily about reformatting/reorganizing.
Although it also adds the limitation from asm labels re statics.
I was hoping to modify the text to say that local register variables can
"only" be used to call Extended asm. This would greatly simplify this
section. But there has been pushback on this (despite the fact that no
one has really suggested any other reasonable use). So I have softened
this, and listed things from the existing docs that are explicitly not
For people who find the HTML easier to review:
Here's the current text:
And here's the new:
WRT your hope to limit this to only uses in extended asms. That'd be
nice, but that's never been an explicit limitation. I would strongly
hesitate to add that limitation at this point in time.