Hi Richard,

> On 29/07/13 14:58, Kyrylo Tkachov wrote:
> > Hi all,
> >
> > Now that combine emits the canonical form for (eq (neg x) (y)) instead
> of (eq
> > (x) (neg y)), this patch fixes up the corresponding pattern in aarch64
> to
> > match that. This enables combine to properly generate the cmn
> instruction
> > where appropriate.
> >
> > Tested aarch64-none-elf on model.
> >
> > Ok for trunk?
> >
> 
> No, this is wrong for inequalities, since in reality it's the second
> operand that's inverted.
> 
> You'll need to use CC_SWP mode and then arrange for this to be correctly
> picked by select_cc_mode.
> 

How's this?

aarch64_select_cc_mode is updated to return CC_SWPmode for these comparisons and
the MD pattern is updated accordingly.

Tested aarch64-none-elf on a model.

Is this ok?

Thanks,
Kyrill

2013-09-09  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

	* config/aarch64/aarch64.c (aarch64_select_cc_mode): Return CC_SWP for
	comparison with negated operand.
	* config/aarch64/aarch64.md (compare_neg<mode>): Match canonical RTL form.
	
2013-09-09  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

	* gcc.target/aarch64/cmn-neg.c: New test.