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Re: [PATCH] PR middle-end/60281
- From: lin zuojian <manjian2006 at gmail dot com>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Thu, 20 Feb 2014 18:46:21 +0800
- Subject: Re: [PATCH] PR middle-end/60281
- Authentication-results: sourceware.org; auth=none
- References: <5305BA80 dot 5080306 at gmail dot com> <20140220085049 dot GD22862 at tucnak dot redhat dot com> <5305C740 dot 6000105 at gmail dot com> <20140220092112 dot GF22862 at tucnak dot redhat dot com>
Oh, you may think my patch have not violated STRICT_ALIGNMENT.My patch
doesn't realign stack_pointer,but virtual_stack_vars,although they may
share the same position mostly.
As you can see,the code emitted just make the stack 8 bytes aligned.
> You mean that for the prologues right now on ARM we emit unaligned
> store insns during expansion and that they are later peepholed into
> aligned stores?
Yes.Because SImode is aligned to 4 bytes ,and str is considered aligned
to 4 bytes on all ARM machine,so gcc doesn't consider itself emitting
the unaligned str instructions in the first place.Of course aligned str
can be peepholed into aligned str multiple.
--
lin zuojian