[PATCH] Make InstCombineCasts.cpp:OptimizeIntToFloatBitCast endian safe

[Ulrich Weigand]

Chris Lattner <clattner at apple.com> wrote on 26.03.2013 00:19:59:
> On Mar 25, 2013, at 12:58 PM, Ulrich Weigand
> <Ulrich.Weigand at de.ibm.com> wrote:
> >
> > The computation of "Elt" above looks to be correct only for
little-endian
> > platforms ...
> >
> > If I disable the whole OptimizeIntToFloatBitCast optimization, I get
the
> > correct result again.
>
> Yes, this does look endian unsafe.  I'd be fine with you disabling
> this when targeting a big-endian system.  It would be nice to
> generalize the code, but it isn't critical at all.

Hmm, this seems to be relatively straightforward after all.
The attached patch fixes the problem for me, and keeps the
optimization enabled for big-endian platforms as well.

OK to commit?

Bye,
Ulrich

(See attached file: diff-llvm-instcombine-endianfix)
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