[PATCH] D117459: [PowerPC] Change CTR clobber estimation for 128-bit floating types

[Qiu Chaofan via Phabricator via llvm-commits]

qiucf created this revision.
qiucf added reviewers: shchenz, jsji, nemanjai, PowerPC.
Herald added subscribers: kbarton, hiraditya.
qiucf requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

- Allow CTR loop for `fp128` operations on Power9 and later CPU
- Specially allow `fneg` for both `ppc_fp128` and `fp128` since we have specialized code lowering them
- Restrict `fpext` and `fptrunc` cast instructions to/from `fp128`, although this fix isn't complete (the value cast may be optimized into pointer cast)

We need a more complete fix to defer CTR clobber judgement after instruction selection. See D81353 <https://reviews.llvm.org/D81353>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D117459

Files:
  llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
  llvm/test/CodeGen/PowerPC/ctrloop-fp128.ll

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