Re: [RFC] arm: use built-in byte swap function
From: Nicolas Pitre
Date: Wed Feb 20 2013 - 23:30:13 EST
On Wed, 20 Feb 2013, Kim Phillips wrote:
> On Wed, 20 Feb 2013 10:43:18 -0500
> Nicolas Pitre <nico@xxxxxxxxxxx> wrote:
> > On Wed, 20 Feb 2013, Woodhouse, David wrote:
> > > On Wed, 2013-02-20 at 09:06 -0500, Nicolas Pitre wrote:
> > > > ... in which case there is no harm shipping a .c file and trivially
> > > > enforcing -O2, the rest being equal.
> > >
> > > For today's compilers, unless the wind changes.
> > We'll adapt if necessary. Going with -O2 should remain pretty safe anyway.
> Alas, not so for gcc 4.4 - I had forgotten I had tested
> Ubuntu/Linaro 4.4.7-1ubuntu2 here:
> add -O2 to that test script and gcc 4.4 *always* emits calls to
> __bswap[sd]i2, even with -march=armv6k+.
Crap. OK, assembly code is the way to go then.
> I'll try working on an assembly version given it probably
> makes more sense, future-gcc-immunity-wise.
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