[PATCH] D22772: GVN-hoist: limit hoisting depth (PR28670)

[Daniel Berlin via llvm-commits]

dberlin added a comment.

Two things:

1. I'd rather not add knobs till we have to. So far, i didn't see that the compile time is being hurt once the other issue is fixed.

Am i missing something?

2. Assuming i missed something and we want to do that, do you have any data on how this magic number affects performance at different numbers?

IE do you have any data that says "100" is right?

It would be ideal to have some data that says:

"at 0, we get no benefit
at 10, we get x benefit and no regressions
..
at 10000, we get x benefit and x regressions"

or something that gives us an idea that "100" is the right knob.


https://reviews.llvm.org/D22772