From: Dave Korn <dave.korn.cygwin@googlemail.com>
To: fearyourself <fearyourself@gmail.com>
Cc: "gcc@gcc.gnu.org" <gcc@gcc.gnu.org>
Subject: Re: Expanding a load instruction
Date: Fri, 05 Jun 2009 15:36:00 -0000 [thread overview]
Message-ID: <4A293E50.4010301@gmail.com> (raw)
In-Reply-To: <c568a2600906050832y1d344449l5aef478548ad3bca@mail.gmail.com>
fearyourself wrote:
> In the instruction set of my architecture, the offsets of a half-load
> (HImode) have to be multiples of 2. However, if I set up a structure
> in a certain way, the compiler will generate:
>
> (mem/s/j:HI (plus:DI (reg:DI 134 [ ivtmp.23 ])
> (const_int 1 [0x1])) [0 <variable>.geno+0 S2 A16])
>
> As the memory operand for the load.
>
> Now, one solution I am going to try to fix this is to use
> define_expand and add a move into another register before this load
> and then load from that register (thus removing the offset of 1).
>
> My question is: Is that how it should be done or is there another solution?
This looks like what you need:
-- Macro: STRICT_ALIGNMENT
Define this macro to be the value 1 if instructions will fail to
work if given data not on the nominal alignment. If instructions
will merely go slower in that case, define this macro as 0.
cheers,
DaveK
next prev parent reply other threads:[~2009-06-05 15:36 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-05 15:32 fearyourself
2009-06-05 15:36 ` Dave Korn [this message]
[not found] ` <c568a2600906051017j799e035cg26ac1c5dd036c16c@mail.gmail.com>
2009-06-09 20:17 ` Jean Christophe Beyler
2009-06-09 22:24 ` Dave Korn
2009-06-10 13:43 ` Jean Christophe Beyler
2009-06-10 14:17 ` Dave Korn
2009-06-10 14:36 ` Jean Christophe Beyler
2009-06-10 15:00 ` Dave Korn
2009-06-11 20:32 ` Jean Christophe Beyler
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