Revert r316887 to fix buildbot failures.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316888 91177308-0d34-0410-b5e6-96231b3b80d8

Author: fhahn

lib/Transforms/Scalar/SCCP.cpp

@@ -30,7 +30,6 @@
 #include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
-#include "llvm/Analysis/ValueLattice.h"
 #include "llvm/Analysis/ValueLatticeUtils.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CallSite.h"
@@ -71,8 +70,6 @@ STATISTIC(NumDeadBlocks , "Number of basic blocks unreachable");
 STATISTIC(IPNumInstRemoved, "Number of instructions removed by IPSCCP");
 STATISTIC(IPNumArgsElimed ,"Number of arguments constant propagated by IPSCCP");
 STATISTIC(IPNumGlobalConst, "Number of globals found to be constant by IPSCCP");
-STATISTIC(IPNumRangeInfoUsed, "Number of times constant range info was used by"
-                              "IPSCCP");
 
 namespace {
 
@@ -177,14 +174,6 @@ class LatticeVal {
     Val.setInt(forcedconstant);
     Val.setPointer(V);
   }
-
-  ValueLatticeElement toValueLattice() const {
-    if (isOverdefined())
-      return ValueLatticeElement::getOverdefined();
-    if (isConstant())
-      return ValueLatticeElement::get(getConstant());
-    return ValueLatticeElement();
-  }
 };
 
 //===----------------------------------------------------------------------===//
@@ -197,8 +186,6 @@ class SCCPSolver : public InstVisitor<SCCPSolver> {
   const TargetLibraryInfo *TLI;
   SmallPtrSet<BasicBlock *, 8> BBExecutable; // The BBs that are executable.
   DenseMap<Value *, LatticeVal> ValueState;  // The state each value is in.
-  // The state each parameter is in.
-  DenseMap<Value *, ValueLatticeElement> ParamState;
 
   /// StructValueState - This maintains ValueState for values that have
   /// StructType, for example for formal arguments, calls, insertelement, etc.
@@ -325,18 +312,10 @@ class SCCPSolver : public InstVisitor<SCCPSolver> {
     return StructValues;
   }
 
-  ValueLatticeElement getLatticeValueFor(Value *V) {
-    std::pair<DenseMap<Value*, ValueLatticeElement>::iterator, bool>
-        PI = ParamState.insert(std::make_pair(V, ValueLatticeElement()));
-    ValueLatticeElement &LV = PI.first->second;
-    if (PI.second) {
-      DenseMap<Value*, LatticeVal>::const_iterator I = ValueState.find(V);
-      assert(I != ValueState.end() &&
-             "V not found in ValueState nor Paramstate map!");
-      LV = I->second.toValueLattice();
-    }
-
-    return LV;
+  LatticeVal getLatticeValueFor(Value *V) const {
+    DenseMap<Value*, LatticeVal>::const_iterator I = ValueState.find(V);
+    assert(I != ValueState.end() && "V is not in valuemap!");
+    return I->second;
   }
 
   /// getTrackedRetVals - Get the inferred return value map.
@@ -465,18 +444,6 @@ class SCCPSolver : public InstVisitor<SCCPSolver> {
     return LV;
   }
 
-  ValueLatticeElement &getParamState(Value *V) {
-    assert(!V->getType()->isStructTy() && "Should use getStructValueState");
-
-    std::pair<DenseMap<Value*, ValueLatticeElement>::iterator, bool>
-        PI = ParamState.insert(std::make_pair(V, ValueLatticeElement()));
-    ValueLatticeElement &LV = PI.first->second;
-    if (PI.second)
-      LV = getValueState(V).toValueLattice();
-
-    return LV;
-  }
-
   /// getStructValueState - Return the LatticeVal object that corresponds to the
   /// value/field pair.  This function handles the case when the value hasn't
   /// been seen yet by properly seeding constants etc.
@@ -1203,9 +1170,6 @@ void SCCPSolver::visitCallSite(CallSite CS) {
           mergeInValue(getStructValueState(&*AI, i), &*AI, CallArg);
         }
       } else {
-        // Most other parts of the Solver still only use the simpler value
-        // lattice, so we propagate changes for parameters to both lattices.
-        getParamState(&*AI).mergeIn(getValueState(*CAI).toValueLattice(), DL);
         mergeInValue(&*AI, getValueState(*CAI));
       }
     }
@@ -1596,43 +1560,6 @@ bool SCCPSolver::ResolvedUndefsIn(Function &F) {
   return false;
 }
 
-static bool tryToReplaceWithConstantRange(SCCPSolver &Solver, Value *V) {
-  bool Changed = false;
-
-  const ValueLatticeElement &IV = Solver.getLatticeValueFor(V);
-  if (IV.isOverdefined())
-    return false;
-
-  // Currently we only use range information for integer values.
-  if (!(V->getType()->isIntegerTy() && IV.isConstantRange()))
-    return false;
-
-  for (auto UI = V->uses().begin(), E = V->uses().end(); UI != E;) {
-    const Use &U = *UI++;
-    auto *Icmp = dyn_cast<ICmpInst>(U.getUser());
-    if (!Icmp || !Solver.isBlockExecutable(Icmp->getParent()))
-      continue;
-
-    auto A = Solver.getLatticeValueFor(Icmp->getOperand(0));
-    auto B = Solver.getLatticeValueFor(Icmp->getOperand(1));
-    Constant *C = nullptr;
-    if (A.satisfiesPredicate(Icmp->getPredicate(), B))
-      C = ConstantInt::getTrue(Icmp->getType());
-    else if (A.satisfiesPredicate(Icmp->getInversePredicate(), B))
-      C = ConstantInt::getFalse(Icmp->getType());
-
-    if (C) {
-      Icmp->replaceAllUsesWith(C);
-      DEBUG(dbgs() << "Replacing " << *Icmp << " with " << *C
-                   << ", because of range information " << A << " " << B
-                   << "\n");
-      Icmp->eraseFromParent();
-      Changed = true;
-    }
-  }
-  return Changed;
-}
-
 static bool tryToReplaceWithConstant(SCCPSolver &Solver, Value *V) {
   Constant *Const = nullptr;
   if (V->getType()->isStructTy()) {
@@ -1650,19 +1577,10 @@ static bool tryToReplaceWithConstant(SCCPSolver &Solver, Value *V) {
     }
     Const = ConstantStruct::get(ST, ConstVals);
   } else {
-    const ValueLatticeElement &IV = Solver.getLatticeValueFor(V);
+    LatticeVal IV = Solver.getLatticeValueFor(V);
     if (IV.isOverdefined())
       return false;
-
-    if (IV.isConstantRange()) {
-      if (IV.getConstantRange().isSingleElement())
-        Const =
-            ConstantInt::get(V->getType(), IV.asConstantInteger().getValue());
-      else
-        return false;
-    } else
-      Const =
-          IV.isConstant() ? IV.getConstant() : UndefValue::get(V->getType());
+    Const = IV.isConstant() ? IV.getConstant() : UndefValue::get(V->getType());
   }
   assert(Const && "Constant is nullptr here!");
   DEBUG(dbgs() << "  Constant: " << *Const << " = " << *V << '\n');
@@ -1863,14 +1781,10 @@ static bool runIPSCCP(Module &M, const DataLayout &DL,
 
     if (Solver.isBlockExecutable(&F.front()))
       for (Function::arg_iterator AI = F.arg_begin(), E = F.arg_end(); AI != E;
-           ++AI) {
+           ++AI)
         if (!AI->use_empty() && tryToReplaceWithConstant(Solver, &*AI))
           ++IPNumArgsElimed;
 
-        if (!AI->use_empty() && tryToReplaceWithConstantRange(Solver, &*AI))
-          ++IPNumRangeInfoUsed;
-      }
-
     for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
       if (!Solver.isBlockExecutable(&*BB)) {
         DEBUG(dbgs() << "  BasicBlock Dead:" << *BB);