1 files changed, 0 insertions, 170 deletions

diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 7f8019dcc72..c7a8d4cad53 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -4125,148 +4125,6 @@ void VectorPromoteHelper::promoteImpl(Instruction *ToBePromoted) {
   Transition->setOperand(getTransitionOriginalValueIdx(), ToBePromoted);
 }
 
-// See if we can speculate calls to intrinsic cttz/ctlz.
-//
-// Example:
-// entry:
-//   ...
-//   %cmp = icmp eq i64 %val, 0
-//   br i1 %cmp, label %end.bb, label %then.bb
-//
-// then.bb:
-//   %c = tail call i64 @llvm.cttz.i64(i64 %val, i1 true)
-//   br label %EndBB
-//
-// end.bb:
-//   %cond = phi i64 [ %c, %then.bb ], [ 64, %entry ]
-//
-// ==>
-//
-// entry:
-//   ...
-//   %c = tail call i64 @llvm.cttz.i64(i64 %val, i1 false)
-//
-static bool OptimizeBranchInst(BranchInst *BrInst, const TargetLowering &TLI) {
-  assert(BrInst->isConditional() && "Expected a conditional branch!");
-  BasicBlock *ThenBB = BrInst->getSuccessor(1);
-  BasicBlock *EndBB = BrInst->getSuccessor(0);
-
-  // See if ThenBB contains only one instruction (excluding the
-  // terminator and DbgInfoIntrinsic calls).
-  IntrinsicInst *II = nullptr;
-  CastInst *CI = nullptr;
-  for (BasicBlock::iterator I = ThenBB->begin(),
-                            E = std::prev(ThenBB->end()); I != E; ++I) {
-    // Skip debug info.
-    if (isa<DbgInfoIntrinsic>(I))
-      continue;
-
-    // Check if this is a zero extension or a truncate of a previously
-    // matched call to intrinsic cttz/ctlz.
-    if (II) {
-      // Early exit if we already found a "free" zero extend/truncate.
-      if (CI)
-        return false;
-
-      Type *SrcTy = II->getType();
-      Type *DestTy = I->getType();
-      Value *V;
- 
-      if (match(cast<Instruction>(I), m_ZExt(m_Value(V))) && V == II) {
-        // Speculate this zero extend only if it is "free" for the target.
-        if (TLI.isZExtFree(SrcTy, DestTy)) {
-          CI = cast<CastInst>(I);
-          continue;
-        }
-      } else if (match(cast<Instruction>(I), m_Trunc(m_Value(V))) && V == II) {
-        // Speculate this truncate only if it is "free" for the target.
-        if (TLI.isTruncateFree(SrcTy, DestTy)) {
-          CI = cast<CastInst>(I);
-          continue;
-        }
-      } else {
-        // Avoid speculating more than one instruction.
-        return false;
-      }
-    }
-
-    // See if this is a call to intrinsic cttz/ctlz.
-    if (match(cast<Instruction>(I), m_Intrinsic<Intrinsic::cttz>())) {
-      // Avoid speculating expensive intrinsic calls.
-      if (!TLI.isCheapToSpeculateCttz())
-        return false;
-    }
-    else if (match(cast<Instruction>(I), m_Intrinsic<Intrinsic::ctlz>())) {
-      // Avoid speculating expensive intrinsic calls.
-      if (!TLI.isCheapToSpeculateCtlz())
-        return false;
-    } else
-      return false;
-    
-    II = cast<IntrinsicInst>(I);
-  }
-
-  // Look for PHI nodes with 'II' as the incoming value from 'ThenBB'.
-  BasicBlock *EntryBB = BrInst->getParent();
-  for (BasicBlock::iterator I = EndBB->begin();
-       PHINode *PN = dyn_cast<PHINode>(I); ++I) {
-    Value *ThenV = PN->getIncomingValueForBlock(ThenBB);
-    Value *OrigV = PN->getIncomingValueForBlock(EntryBB);
-
-    if (!OrigV)
-      return false;
-
-    if (ThenV != II && (!CI || ThenV != CI))
-      return false;
-    
-    if (ConstantInt *CInt = dyn_cast<ConstantInt>(OrigV)) {
-      unsigned BitWidth = II->getType()->getIntegerBitWidth();
-
-      // Don't try to simplify this phi node if 'ThenV' is a cttz/ctlz
-      // intrinsic call, but 'OrigV' is not equal to the 'size-of' in bits
-      // of the value in input to the cttz/ctlz.
-      if (CInt->getValue() != BitWidth)
-        return false;
-
-      // Hoist the call to cttz/ctlz from ThenBB into EntryBB.
-      EntryBB->getInstList().splice(BrInst, ThenBB->getInstList(),
-                                    ThenBB->begin(), std::prev(ThenBB->end()));
- 
-      // Update PN setting ThenV as the incoming value from both 'EntryBB'
-      // and 'ThenBB'. Eventually, method 'OptimizeInst' will fold this
-      // phi node if all the incoming values are the same.
-      PN->setIncomingValue(PN->getBasicBlockIndex(EntryBB), ThenV);
-      PN->setIncomingValue(PN->getBasicBlockIndex(ThenBB), ThenV);
-
-      // Clear the 'undef on zero' flag of the cttz/ctlz intrinsic call.
-      if (cast<ConstantInt>(II->getArgOperand(1))->isOne()) {
-        Type *Ty = II->getArgOperand(0)->getType();
-        Value *Args[] = { II->getArgOperand(0),
-                          ConstantInt::getFalse(II->getContext()) };
-        Module *M = EntryBB->getParent()->getParent();
-        Value *IF = Intrinsic::getDeclaration(M, II->getIntrinsicID(), Ty);
-        IRBuilder<> Builder(II);
-        Instruction *NewI = Builder.CreateCall(IF, Args);
-
-        // Replace the old call to cttz/ctlz.
-        II->replaceAllUsesWith(NewI);
-        II->eraseFromParent();
-      }
- 
-      // Update BrInst condition so that the branch to EndBB is always taken.
-      // Later on, method 'ConstantFoldTerminator' will simplify this branch
-      // replacing it with a direct branch to 'EndBB'.
-      // As a side effect, CodeGenPrepare will attempt to simplify the control
-      // flow graph by deleting basic block 'ThenBB' and merging 'EntryBB' into
-      // 'EndBB' (calling method 'EliminateFallThrough').
-      BrInst->setCondition(ConstantInt::getTrue(BrInst->getContext()));
-      return true;
-    }
-  }
-
-  return false;
-}
-
 /// Some targets can do store(extractelement) with one instruction.
 /// Try to push the extractelement towards the stores when the target
 /// has this feature and this is profitable.
@@ -4419,34 +4277,6 @@ bool CodeGenPrepare::OptimizeInst(Instruction *I, bool& ModifiedDT) {
   if (isa<ExtractElementInst>(I))
     return OptimizeExtractElementInst(I);
 
-  if (BranchInst *BI = dyn_cast<BranchInst>(I)) {
-    if (TLI && BI->isConditional() && BI->getCondition()->hasOneUse()) {
-      // Check if the branch condition compares a value agaist zero.
-      if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition())) {
-        if (ICI->getPredicate() == ICmpInst::ICMP_EQ &&
-            match(ICI->getOperand(1), m_Zero())) {
-          BasicBlock *ThenBB = BI->getSuccessor(1);
-          BasicBlock *EndBB = BI->getSuccessor(0);
-
-          // Check if ThenBB is only reachable from this basic block; also,
-          // check if EndBB has more than one predecessor.
-          if (ThenBB->getSinglePredecessor() &&
-              !EndBB->getSinglePredecessor()) {
-            TerminatorInst *TI = ThenBB->getTerminator();
-
-            if (TI->getNumSuccessors() == 1 && TI->getSuccessor(0) == EndBB &&
-                // Try to speculate calls to intrinsic cttz/ctlz from 'ThenBB'.
-                OptimizeBranchInst(BI, *TLI)) {
-              ModifiedDT = true;
-              return true;
-            }
-          }
-        }
-      }
-    }
-    return false;
-  }
-
   return false;
 }