1 files changed, 2 insertions, 112 deletions

diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp
index 74e310f7e7..9cd538128b 100644
--- a/lib/Transforms/Scalar/CodeGenPrepare.cpp
+++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp
@@ -18,7 +18,6 @@
 #include "llvm/Constants.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/Function.h"
-#include "llvm/GlobalVariable.h"
 #include "llvm/IRBuilder.h"
 #include "llvm/InlineAsm.h"
 #include "llvm/Instructions.h"
@@ -128,7 +127,6 @@ namespace {
     bool OptimizeSelectInst(SelectInst *SI);
     bool DupRetToEnableTailCallOpts(ReturnInst *RI);
     bool PlaceDbgValues(Function &F);
-    bool ConvertLoadToSwitch(LoadInst *LI);
   };
 }
 
@@ -1292,11 +1290,9 @@ bool CodeGenPrepare::OptimizeInst(Instruction *I) {
     return OptimizeCmpExpression(CI);
 
   if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
-    bool Changed = false;
     if (TLI)
-      Changed |= OptimizeMemoryInst(I, I->getOperand(0), LI->getType());
-    Changed |= ConvertLoadToSwitch(LI);
-    return Changed;
+      return OptimizeMemoryInst(I, I->getOperand(0), LI->getType());
+    return false;
   }
 
   if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
@@ -1376,109 +1372,3 @@ bool CodeGenPrepare::PlaceDbgValues(Function &F) {
   }
   return MadeChange;
 }
-
-static bool TargetSupportsJumpTables(const TargetLowering &TLI) {
-  return TLI.supportJumpTables() &&
-          (TLI.isOperationLegalOrCustom(ISD::BR_JT, MVT::Other) ||
-           TLI.isOperationLegalOrCustom(ISD::BRIND, MVT::Other));
-}
-
-/// ConvertLoadToSwitch - Convert loads from constant lookup tables into
-/// switches. This undos the switch-to-lookup table transformation in
-/// SimplifyCFG for targets where that is inprofitable.
-bool CodeGenPrepare::ConvertLoadToSwitch(LoadInst *LI) {
-  // This only applies to targets that don't support jump tables.
-  if (!TLI || TargetSupportsJumpTables(*TLI))
-    return false;
-
-  // FIXME: In the future, it would be desirable to have enough target
-  // information in SimplifyCFG, so we could decide at that stage whether to
-  // transform the switch to a lookup table or not, and this
-  // reverse-transformation could be removed.
-
-  GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(LI->getPointerOperand());
-  if (!GEP || !GEP->isInBounds() || GEP->getPointerAddressSpace())
-    return false;
-  if (GEP->getNumIndices() != 2)
-    return false;
-  Value *FirstIndex = GEP->idx_begin()[0];
-  ConstantInt *FirstIndexInt = dyn_cast<ConstantInt>(FirstIndex);
-  if (!FirstIndexInt || !FirstIndexInt->isZero())
-    return false;
-
-  Value *TableIndex = GEP->idx_begin()[1];
-  IntegerType *TableIndexTy = cast<IntegerType>(TableIndex->getType());
-
-  GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getPointerOperand());
-  if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer())
-    return false;
-
-  Constant *Arr = GV->getInitializer();
-  uint64_t NumElements;
-  if (ConstantArray *CA = dyn_cast<ConstantArray>(Arr))
-    NumElements = CA->getType()->getNumElements();
-  else if (ConstantDataArray *CDA = dyn_cast<ConstantDataArray>(Arr))
-    NumElements = CDA->getNumElements();
-  else
-    return false;
-  if (NumElements < 2)
-    return false;
-
-  // Split the block.
-  BasicBlock *OriginalBB = LI->getParent();
-  BasicBlock *PostSwitchBB = OriginalBB->splitBasicBlock(LI);
-
-  // Replace OriginalBB's terminator with a switch.
-  IRBuilder<> Builder(OriginalBB->getTerminator());
-  SwitchInst *Switch = Builder.CreateSwitch(TableIndex, PostSwitchBB,
-                                            NumElements - 1);
-  OriginalBB->getTerminator()->eraseFromParent();
-
-  // Count the frequency of each value to decide which to use as default.
-  SmallDenseMap<Constant*, uint64_t> ValueFreq;
-  for (uint64_t I = 0; I < NumElements; ++I)
-    ++ValueFreq[Arr->getAggregateElement(I)];
-  uint64_t MaxCount = 0;
-  Constant *DefaultValue = NULL;
-  for (SmallDenseMap<Constant*, uint64_t>::iterator I = ValueFreq.begin(),
-       E = ValueFreq.end(); I != E; ++I) {
-    if (I->second > MaxCount) {
-      MaxCount = I->second;
-      DefaultValue = I->first;
-    }
-  }
-  assert(DefaultValue && "No values in the array?");
-
-  // Create the phi node in PostSwitchBB, which will replace the load.
-  Builder.SetInsertPoint(PostSwitchBB->begin());
-  PHINode *PHI = Builder.CreatePHI(LI->getType(), NumElements);
-  PHI->addIncoming(DefaultValue, OriginalBB);
-
-  // Build basic blocks to target with the switch.
-  for (uint64_t I = 0; I < NumElements; ++I) {
-    Constant *C = Arr->getAggregateElement(I);
-    if (C == DefaultValue) continue; // Already covered by the default case.
-
-    BasicBlock *BB = BasicBlock::Create(PostSwitchBB->getContext(),
-                                        "lookup.bb",
-                                        PostSwitchBB->getParent(),
-                                        PostSwitchBB);
-    Switch->addCase(ConstantInt::get(TableIndexTy, I), BB);
-    Builder.SetInsertPoint(BB);
-    Builder.CreateBr(PostSwitchBB);
-    PHI->addIncoming(C, BB);
-  }
-
-  // Remove the load.
-  LI->replaceAllUsesWith(PHI);
-  LI->eraseFromParent();
-
-  // Clean up.
-  if (GEP->use_empty())
-    GEP->eraseFromParent();
-  if (GV->hasUnnamedAddr() && GV->hasPrivateLinkage() && GV->use_empty())
-    GV->eraseFromParent();
-
-  CurInstIterator = Switch;
-  return true;
-}