[PATCH] D43079: [TTI CostModel] change default cost of FP ops to 1 (PR36280)

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

@fhahn wrote (but it didn't transfer here):

> I have not thought this through fully yet, but couldn't we use the scheduling model to get the number of units available
>  for certain instructions for backends using the machine scheduler? And determine the throughput based on that?

Yes, I thought about that too. We already use the sched model to get instruction latency and to let the unroller know the size of the reorder buffer, so using that for throughputs and/or uops shouldn't be too hard.

But we'll have to check how exactly these costs are being used. By using a more realistic cost model, we may get into more trouble because clients may have bent the costs to match their own cost formula rather than an accurate hardware model.


Repository:
  rL LLVM

https://reviews.llvm.org/D43079