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.tkac...@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.tkac...@arm.com>
* gcc.target/aarch64/cmn-neg.c: New test.
aarch64-cmn.patch
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