[llvm-commits] CVS: llvm/lib/Target/X86/X86InstrFPStack.td X86InstrInfo.cpp X86InstrInfo.h X86InstrInfo.td X86InstrMMX.td X86InstrSSE.td

[Chris Lattner]

>> This achieves two things:
>>
>> 1. Just looking at the .td file, you can tell which instructions are
>> candidates for remat.
>> 2. The isRematerializable predicate is faster for instructions that
>> are not remat-able.
>> 3. The isReallyRematerializable only needs to be implemented by
>> targets with instructions that are remat-able only in some cases
>> (like the x86 instructions).
>
> I okay'd Dan patch after considering the trade-offs. To me this gets
> rid of the duplicate instructions so it's worth it.

I think both approaches get rid of the duplicate instructions.

> If we are really concerned about the speed, then I agree the hybrid
> approach is the best. Sorry about the confusion.

Speed is something to consider, but I don't think it should override  
maintainability.

> Not to mention I had already considered the "trivial  
> rematerialization"
> scheme to be temporary.

Okay, how do you think this should work going forward?

-Chris