1 files changed, 0 insertions, 382 deletions

diff --git a/contrib/llvm/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp b/contrib/llvm/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
deleted file mode 100644
index 0d67c0d740ec..000000000000
--- a/contrib/llvm/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
+++ /dev/null
@@ -1,382 +0,0 @@
-//===- LowerExpectIntrinsic.cpp - Lower expect intrinsic ------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass lowers the 'expect' intrinsic to LLVM metadata.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Transforms/Scalar/LowerExpectIntrinsic.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/iterator_range.h"
-#include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/Intrinsics.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/MDBuilder.h"
-#include "llvm/IR/Metadata.h"
-#include "llvm/Pass.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Transforms/Scalar.h"
-
-using namespace llvm;
-
-#define DEBUG_TYPE "lower-expect-intrinsic"
-
-STATISTIC(ExpectIntrinsicsHandled,
-          "Number of 'expect' intrinsic instructions handled");
-
-// These default values are chosen to represent an extremely skewed outcome for
-// a condition, but they leave some room for interpretation by later passes.
-//
-// If the documentation for __builtin_expect() was made explicit that it should
-// only be used in extreme cases, we could make this ratio higher. As it stands,
-// programmers may be using __builtin_expect() / llvm.expect to annotate that a
-// branch is likely or unlikely to be taken.
-//
-// There is a known dependency on this ratio in CodeGenPrepare when transforming
-// 'select' instructions. It may be worthwhile to hoist these values to some
-// shared space, so they can be used directly by other passes.
-
-static cl::opt<uint32_t> LikelyBranchWeight(
-    "likely-branch-weight", cl::Hidden, cl::init(2000),
-    cl::desc("Weight of the branch likely to be taken (default = 2000)"));
-static cl::opt<uint32_t> UnlikelyBranchWeight(
-    "unlikely-branch-weight", cl::Hidden, cl::init(1),
-    cl::desc("Weight of the branch unlikely to be taken (default = 1)"));
-
-static bool handleSwitchExpect(SwitchInst &SI) {
-  CallInst *CI = dyn_cast<CallInst>(SI.getCondition());
-  if (!CI)
-    return false;
-
-  Function *Fn = CI->getCalledFunction();
-  if (!Fn || Fn->getIntrinsicID() != Intrinsic::expect)
-    return false;
-
-  Value *ArgValue = CI->getArgOperand(0);
-  ConstantInt *ExpectedValue = dyn_cast<ConstantInt>(CI->getArgOperand(1));
-  if (!ExpectedValue)
-    return false;
-
-  SwitchInst::CaseHandle Case = *SI.findCaseValue(ExpectedValue);
-  unsigned n = SI.getNumCases(); // +1 for default case.
-  SmallVector<uint32_t, 16> Weights(n + 1, UnlikelyBranchWeight);
-
-  if (Case == *SI.case_default())
-    Weights[0] = LikelyBranchWeight;
-  else
-    Weights[Case.getCaseIndex() + 1] = LikelyBranchWeight;
-
-  SI.setMetadata(LLVMContext::MD_prof,
-                 MDBuilder(CI->getContext()).createBranchWeights(Weights));
-
-  SI.setCondition(ArgValue);
-  return true;
-}
-
-/// Handler for PHINodes that define the value argument to an
-/// @llvm.expect call.
-///
-/// If the operand of the phi has a constant value and it 'contradicts'
-/// with the expected value of phi def, then the corresponding incoming
-/// edge of the phi is unlikely to be taken. Using that information,
-/// the branch probability info for the originating branch can be inferred.
-static void handlePhiDef(CallInst *Expect) {
-  Value &Arg = *Expect->getArgOperand(0);
-  ConstantInt *ExpectedValue = dyn_cast<ConstantInt>(Expect->getArgOperand(1));
-  if (!ExpectedValue)
-    return;
-  const APInt &ExpectedPhiValue = ExpectedValue->getValue();
-
-  // Walk up in backward a list of instructions that
-  // have 'copy' semantics by 'stripping' the copies
-  // until a PHI node or an instruction of unknown kind
-  // is reached. Negation via xor is also handled.
-  //
-  //       C = PHI(...);
-  //       B = C;
-  //       A = B;
-  //       D = __builtin_expect(A, 0);
-  //
-  Value *V = &Arg;
-  SmallVector<Instruction *, 4> Operations;
-  while (!isa<PHINode>(V)) {
-    if (ZExtInst *ZExt = dyn_cast<ZExtInst>(V)) {
-      V = ZExt->getOperand(0);
-      Operations.push_back(ZExt);
-      continue;
-    }
-
-    if (SExtInst *SExt = dyn_cast<SExtInst>(V)) {
-      V = SExt->getOperand(0);
-      Operations.push_back(SExt);
-      continue;
-    }
-
-    BinaryOperator *BinOp = dyn_cast<BinaryOperator>(V);
-    if (!BinOp || BinOp->getOpcode() != Instruction::Xor)
-      return;
-
-    ConstantInt *CInt = dyn_cast<ConstantInt>(BinOp->getOperand(1));
-    if (!CInt)
-      return;
-
-    V = BinOp->getOperand(0);
-    Operations.push_back(BinOp);
-  }
-
-  // Executes the recorded operations on input 'Value'.
-  auto ApplyOperations = [&](const APInt &Value) {
-    APInt Result = Value;
-    for (auto Op : llvm::reverse(Operations)) {
-      switch (Op->getOpcode()) {
-      case Instruction::Xor:
-        Result ^= cast<ConstantInt>(Op->getOperand(1))->getValue();
-        break;
-      case Instruction::ZExt:
-        Result = Result.zext(Op->getType()->getIntegerBitWidth());
-        break;
-      case Instruction::SExt:
-        Result = Result.sext(Op->getType()->getIntegerBitWidth());
-        break;
-      default:
-        llvm_unreachable("Unexpected operation");
-      }
-    }
-    return Result;
-  };
-
-  auto *PhiDef = dyn_cast<PHINode>(V);
-
-  // Get the first dominating conditional branch of the operand
-  // i's incoming block.
-  auto GetDomConditional = [&](unsigned i) -> BranchInst * {
-    BasicBlock *BB = PhiDef->getIncomingBlock(i);
-    BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
-    if (BI && BI->isConditional())
-      return BI;
-    BB = BB->getSinglePredecessor();
-    if (!BB)
-      return nullptr;
-    BI = dyn_cast<BranchInst>(BB->getTerminator());
-    if (!BI || BI->isUnconditional())
-      return nullptr;
-    return BI;
-  };
-
-  // Now walk through all Phi operands to find phi oprerands with values
-  // conflicting with the expected phi output value. Any such operand
-  // indicates the incoming edge to that operand is unlikely.
-  for (unsigned i = 0, e = PhiDef->getNumIncomingValues(); i != e; ++i) {
-
-    Value *PhiOpnd = PhiDef->getIncomingValue(i);
-    ConstantInt *CI = dyn_cast<ConstantInt>(PhiOpnd);
-    if (!CI)
-      continue;
-
-    // Not an interesting case when IsUnlikely is false -- we can not infer
-    // anything useful when the operand value matches the expected phi
-    // output.
-    if (ExpectedPhiValue == ApplyOperations(CI->getValue()))
-      continue;
-
-    BranchInst *BI = GetDomConditional(i);
-    if (!BI)
-      continue;
-
-    MDBuilder MDB(PhiDef->getContext());
-
-    // There are two situations in which an operand of the PhiDef comes
-    // from a given successor of a branch instruction BI.
-    // 1) When the incoming block of the operand is the successor block;
-    // 2) When the incoming block is BI's enclosing block and the
-    // successor is the PhiDef's enclosing block.
-    //
-    // Returns true if the operand which comes from OpndIncomingBB
-    // comes from outgoing edge of BI that leads to Succ block.
-    auto *OpndIncomingBB = PhiDef->getIncomingBlock(i);
-    auto IsOpndComingFromSuccessor = [&](BasicBlock *Succ) {
-      if (OpndIncomingBB == Succ)
-        // If this successor is the incoming block for this
-        // Phi operand, then this successor does lead to the Phi.
-        return true;
-      if (OpndIncomingBB == BI->getParent() && Succ == PhiDef->getParent())
-        // Otherwise, if the edge is directly from the branch
-        // to the Phi, this successor is the one feeding this
-        // Phi operand.
-        return true;
-      return false;
-    };
-
-    if (IsOpndComingFromSuccessor(BI->getSuccessor(1)))
-      BI->setMetadata(
-          LLVMContext::MD_prof,
-          MDB.createBranchWeights(LikelyBranchWeight, UnlikelyBranchWeight));
-    else if (IsOpndComingFromSuccessor(BI->getSuccessor(0)))
-      BI->setMetadata(
-          LLVMContext::MD_prof,
-          MDB.createBranchWeights(UnlikelyBranchWeight, LikelyBranchWeight));
-  }
-}
-
-// Handle both BranchInst and SelectInst.
-template <class BrSelInst> static bool handleBrSelExpect(BrSelInst &BSI) {
-
-  // Handle non-optimized IR code like:
-  //   %expval = call i64 @llvm.expect.i64(i64 %conv1, i64 1)
-  //   %tobool = icmp ne i64 %expval, 0
-  //   br i1 %tobool, label %if.then, label %if.end
-  //
-  // Or the following simpler case:
-  //   %expval = call i1 @llvm.expect.i1(i1 %cmp, i1 1)
-  //   br i1 %expval, label %if.then, label %if.end
-
-  CallInst *CI;
-
-  ICmpInst *CmpI = dyn_cast<ICmpInst>(BSI.getCondition());
-  CmpInst::Predicate Predicate;
-  ConstantInt *CmpConstOperand = nullptr;
-  if (!CmpI) {
-    CI = dyn_cast<CallInst>(BSI.getCondition());
-    Predicate = CmpInst::ICMP_NE;
-  } else {
-    Predicate = CmpI->getPredicate();
-    if (Predicate != CmpInst::ICMP_NE && Predicate != CmpInst::ICMP_EQ)
-      return false;
-
-    CmpConstOperand = dyn_cast<ConstantInt>(CmpI->getOperand(1));
-    if (!CmpConstOperand)
-      return false;
-    CI = dyn_cast<CallInst>(CmpI->getOperand(0));
-  }
-
-  if (!CI)
-    return false;
-
-  uint64_t ValueComparedTo = 0;
-  if (CmpConstOperand) {
-    if (CmpConstOperand->getBitWidth() > 64)
-      return false;
-    ValueComparedTo = CmpConstOperand->getZExtValue();
-  }
-
-  Function *Fn = CI->getCalledFunction();
-  if (!Fn || Fn->getIntrinsicID() != Intrinsic::expect)
-    return false;
-
-  Value *ArgValue = CI->getArgOperand(0);
-  ConstantInt *ExpectedValue = dyn_cast<ConstantInt>(CI->getArgOperand(1));
-  if (!ExpectedValue)
-    return false;
-
-  MDBuilder MDB(CI->getContext());
-  MDNode *Node;
-
-  if ((ExpectedValue->getZExtValue() == ValueComparedTo) ==
-      (Predicate == CmpInst::ICMP_EQ))
-    Node = MDB.createBranchWeights(LikelyBranchWeight, UnlikelyBranchWeight);
-  else
-    Node = MDB.createBranchWeights(UnlikelyBranchWeight, LikelyBranchWeight);
-
-  BSI.setMetadata(LLVMContext::MD_prof, Node);
-
-  if (CmpI)
-    CmpI->setOperand(0, ArgValue);
-  else
-    BSI.setCondition(ArgValue);
-  return true;
-}
-
-static bool handleBranchExpect(BranchInst &BI) {
-  if (BI.isUnconditional())
-    return false;
-
-  return handleBrSelExpect<BranchInst>(BI);
-}
-
-static bool lowerExpectIntrinsic(Function &F) {
-  bool Changed = false;
-
-  for (BasicBlock &BB : F) {
-    // Create "block_weights" metadata.
-    if (BranchInst *BI = dyn_cast<BranchInst>(BB.getTerminator())) {
-      if (handleBranchExpect(*BI))
-        ExpectIntrinsicsHandled++;
-    } else if (SwitchInst *SI = dyn_cast<SwitchInst>(BB.getTerminator())) {
-      if (handleSwitchExpect(*SI))
-        ExpectIntrinsicsHandled++;
-    }
-
-    // Remove llvm.expect intrinsics. Iterate backwards in order
-    // to process select instructions before the intrinsic gets
-    // removed.
-    for (auto BI = BB.rbegin(), BE = BB.rend(); BI != BE;) {
-      Instruction *Inst = &*BI++;
-      CallInst *CI = dyn_cast<CallInst>(Inst);
-      if (!CI) {
-        if (SelectInst *SI = dyn_cast<SelectInst>(Inst)) {
-          if (handleBrSelExpect(*SI))
-            ExpectIntrinsicsHandled++;
-        }
-        continue;
-      }
-
-      Function *Fn = CI->getCalledFunction();
-      if (Fn && Fn->getIntrinsicID() == Intrinsic::expect) {
-        // Before erasing the llvm.expect, walk backward to find
-        // phi that define llvm.expect's first arg, and
-        // infer branch probability:
-        handlePhiDef(CI);
-        Value *Exp = CI->getArgOperand(0);
-        CI->replaceAllUsesWith(Exp);
-        CI->eraseFromParent();
-        Changed = true;
-      }
-    }
-  }
-
-  return Changed;
-}
-
-PreservedAnalyses LowerExpectIntrinsicPass::run(Function &F,
-                                                FunctionAnalysisManager &) {
-  if (lowerExpectIntrinsic(F))
-    return PreservedAnalyses::none();
-
-  return PreservedAnalyses::all();
-}
-
-namespace {
-/// Legacy pass for lowering expect intrinsics out of the IR.
-///
-/// When this pass is run over a function it uses expect intrinsics which feed
-/// branches and switches to provide branch weight metadata for those
-/// terminators. It then removes the expect intrinsics from the IR so the rest
-/// of the optimizer can ignore them.
-class LowerExpectIntrinsic : public FunctionPass {
-public:
-  static char ID;
-  LowerExpectIntrinsic() : FunctionPass(ID) {
-    initializeLowerExpectIntrinsicPass(*PassRegistry::getPassRegistry());
-  }
-
-  bool runOnFunction(Function &F) override { return lowerExpectIntrinsic(F); }
-};
-}
-
-char LowerExpectIntrinsic::ID = 0;
-INITIALIZE_PASS(LowerExpectIntrinsic, "lower-expect",
-                "Lower 'expect' Intrinsics", false, false)
-
-FunctionPass *llvm::createLowerExpectIntrinsicPass() {
-  return new LowerExpectIntrinsic();
-}