[PATCH] D73588: AMDGPU: Enhancement on FDIV lowering in AMDGPUCodeGenPrepare

[Changpeng Fang via Phabricator via llvm-commits]

cfang created this revision.
cfang added reviewers: arsenm, b-sumner.
Herald added subscribers: kerbowa, hiraditya, t-tye, tpr, dstuttard, yaxunl, nhaehnle, wdng, jvesely, kzhuravl.
Herald added a project: LLVM.

This is to enhance the work in https://reviews.llvm.org/D71293.

1. We change the fpmath accuracy threshold for rcp from 2.5 to 1.0 ULP. This is cased on the accuracy that rcp can achieve in the hardware.
2. We do fdiv re-association only with unsafe-math  or reciprocal-math (fast-math implies reciprocal-math).


https://reviews.llvm.org/D73588

Files:
  llvm/lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp
  llvm/lib/Target/AMDGPU/SIISelLowering.cpp
  llvm/test/CodeGen/AMDGPU/amdgpu-codegenprepare-fdiv.ll
  llvm/test/CodeGen/AMDGPU/fdiv.f16.ll

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