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From: Segher Boessenkool <segher@kernel.crashing.org>
Subject: Re: [RFC/PATCH] powerpc: Always use -mno-string & -mno-multiple
Date: Thu, 22 Mar 2007 13:02:42 +0100
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Akinobu Mita <mita@fixstars.com>, Paul Mackerras <paulus@samba.org>,
	linuxppc-dev list <linuxppc-dev@ozlabs.org>
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> powerpc: Always use -mno-string and -mno-multiple
>
> The string and multiple load/store instructions are causing more
> damage than help on a lot of processors where they are microcoded
> and are generally no good for the kernel to use. Let's make sure
> we don't emit them on any powerpc variant.

And they help a lot on many 32-bit CPUs.  NAK.

If you tell your GCC to compile for a certain CPU where
these insns would be very slow, GCC will automagically
not generate them, already.


Segher