[LLVMdev] Strong vs. default phi elimination and single-reg classes

[Jakob Stoklund Olesen]

On Jun 8, 2012, at 9:02 AM, Hal Finkel <hfinkel at anl.gov> wrote:

> On Fri, 8 Jun 2012 08:49:32 -0700
> Jakob Stoklund Olesen <stoklund at 2pi.dk> wrote:

>> When machine code is still in SSA form, there are restrictions on
>> what can be done with physical registers, which by their nature can't
>> be in SSA form. Lang and I have been trying to come up with some
>> rules, but we haven't found the right set yet.

> [We should add this to the docs somewhere].

http://llvm.org/bugs/show_bug.cgi?id=13058

>> Unfortunately, that breaks your TCRETURNri instructions. Sorry!
> 
> I'm guessing that I can rewrite TCRETURN to reference CTR/CTR8
> directly. I'll have to try that.

That should be possible, yes.

/jakob