[PATCH] D71883: [PowerPC] Use PredictableSelectIsExpensive to enable select to branch in CGP

[Zhang Kang via Phabricator via llvm-commits]

ZhangKang created this revision.
Herald added subscribers: llvm-commits, shchenz, jsji, kbarton, hiraditya, kristof.beyls, nemanjai.
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There is a patch D19488 <https://reviews.llvm.org/D19488>: [CodeGenPrepare] use branch weight metadata to decide if a select should be turned into a branch,  this patch is for CGP, it will try to convert `SELECT` to branch based on the `BranchProbability`, when the `BranchProbability` more than `MinPercentageForPredictableBranch`(default value is 99%).
The variable `PredictableSelectExpensive` can be set whether we will do this `SELECT to branch` optimization, the default value is false.  Now only ARM and X86 has set this variable like this:

For PPC, we should also set the variable `PredictableSelectIsExpensive` to do the `select to if` based on `BranchProbability` in CodeGenPrepare.


https://reviews.llvm.org/D71883

Files:
  llvm/lib/Target/PowerPC/PPC.td
  llvm/lib/Target/PowerPC/PPCISelLowering.cpp
  llvm/lib/Target/PowerPC/PPCSubtarget.h
  llvm/test/CodeGen/PowerPC/select-to-branch.mir

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