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Re: [PATCH 1/7] Fix GTY markup of u2
- From: Michael Matz <matz at suse dot de>
- To: Mike Stump <mikestump at comcast dot net>
- Cc: Richard Sandiford <rdsandiford at googlemail dot com>, gcc-patches at gcc dot gnu dot org
- Date: Mon, 12 May 2014 12:19:11 +0200 (CEST)
- Subject: Re: [PATCH 1/7] Fix GTY markup of u2
- Authentication-results: sourceware.org; auth=none
- References: <87a9ap1k8n dot fsf at talisman dot default> <8761ld1k4o dot fsf at talisman dot default> <E5677A80-2E13-420C-B0DF-C098469B1789 at comcast dot net>
Hi,
On Sat, 10 May 2014, Mike Stump wrote:
> > The rtx u2 field currently uses a desc/tag pair for GTY. This seems
> > unnecessary though,
>
> > OK to install?
>
> Ick. I don’t favor skip. The change feels like a premature
> optimization that doesn’t net any code gen benefit. I’ll defer to a gty
> person if they prefer skip.
The skip is necessary, otherwise union members of GTY structs are required
to have a 'desc' (and their members in turn are required to have a 'tag').
So it's either the skip or the desc/tag pair. The code-gen difference is
one empty (but two-cased) switch statement less.
Ciao,
Michael.