[PATCH] rs6000: Use xori for HTM builtins and vector compares
Wed Sep 10 20:20:00 GMT 2014
On Wed, 2014-09-10 at 14:29 -0500, Segher Boessenkool wrote:
> Huh, interesting. I assumed 1-(0_or_1) and (0_or_1)^1 would look the
> same to combine, but no.
> With subfic, combine optimises it all to a branch on cr0. With xori,
> for some reason combine has a much easier job, and it optimises the lot
> to a copy of cr0 to some cc, and then branch on that. The RA of course
> gets rid of the copy. The extra freedom will more likely help than hurt.
> The simple testcase ends up as just "tbegin. 0; beqlr 0" in either case.
> So, okay?
No objections from me then.
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