Another problem with "Recommit r265547, and r265610, r265639, r265657"

[Wei Mi via llvm-commits]

>> Instruction with a tied operand is not triviallyRematerializable so
>> the problem shouldn't appear either. If that problem still exists with
>> your patch in RegisterCoalescer, we need to look deeply into what is
>> wrong there to come up a better fix.
>
>
> The problem still exists if only using my fix in RegisterCoalescer.
>
> However, if applying your patch http://reviews.llvm.org/D19486 it goes away.
> Do you intend to push that?
>
> For a while I thought your patch wouldn't be necessary with the
> RegisterCoalescer change, but maybe it is for the tied-operand case then?
>
> Thanks,
> Mikael
>

I plan to push http://reviews.llvm.org/D19486 but change the
triviallyRematerializable condition to an assertion, i.e., I expect no
instruction entering DeadRemat will be non-triviallyRematerializable.

For the tied-operand case, could you send me a debug trace like you
sent last time, I can look at how a non-triviallyRematerializable inst
makes its way to DeadRemat.

Thanks,
Wei.