[RFC,PATCH] Using equivalences to help eliminate_regs_in_insn

[Vladimir N Makarov]

On 09/06/2016 11:22 AM, Matthew Fortune wrote:
> There is an implementation that optimises a single set but not one for
> a REG_EQUAL. Do you have any recollection of this code and do you think
> there was a reason you didn't implement the REG_EQUAL case? Either way
> any advice on my approach is welcome.
Matt, sorry for delay with the answer.  I had a long vacation.

I did not write the code.  I mostly took it from the old register 
allocator practically without any changes.
Looking at your prototype patch, I think you are doing an optimization 
which can be important for many targets.  Moreover, the optimization 
probably will be frequently applied for these targets.

I believe you should produce a final patch, test it well and submit it.

Thank you for finding the optimization opportunity and working on 
implementing it.