[Mlir-commits] [mlir] [mlir][Arith] Add FTZ (Flush-to-Zero) fast-math flag (PR #112700)

[Jakub Kuderski]

kuhar wrote:

We had a brief offline chat about this today. Leaving a comment just so that I forgot what we talked about. This is based on my understanding, I should verify this:
* fast math adds assumptions but does not change semantics, should be safe to drop
* rounding modes change semantics and cannot be simply dropped

I think what we want is a rounding mode attr with well defined behavior that in the general case cannot be dropped / ignored during lowering. If SPIR-V doesn't support something, it should be clear that we are sacrificing correctness during lowering, but this shouldn't block us having these rounding modes for targets that can support it.

https://github.com/llvm/llvm-project/pull/112700