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[Bug target/43440] Overwriting neon quad register does not clobber all included single registers
- From: "ramana at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 21 Mar 2010 13:41:44 -0000
- Subject: [Bug target/43440] Overwriting neon quad register does not clobber all included single registers
- References: <bug-43440-18938@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #9 from ramana at gcc dot gnu dot org 2010-03-21 13:41 -------
(In reply to comment #8)
> What about just forbidding to use "q" registers in the inline assembly clobber
> list? Is it difficult to do?
>
It's not difficult to -
The patch only penalises the cases where an s<reg> ends up clobbering another
s<reg> in the same quad (or double for that matter) but the common case of the
q<reg> or the d<reg> clobbering the s<reg> in the same quad is a necessity and
correctness. Thus if we wanted to allow q<reg> and d<reg> in the clobber list
then we need to live with this restriction.
Ramana
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43440