Revert "[SCCP] Propagate integer range info for parameters in IPSCCP."

This reverts commit r315288. This is part of fixing segfault introduced
in:

http://green.lab.llvm.org/green/job/clang-stage2-configure-Rlto/21675/

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315329 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 90 deletions

diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index b0f58367c94..4822cf7cce0 100644
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -27,7 +27,6 @@
 #include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
-#include "llvm/Analysis/ValueLattice.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DataLayout.h"
@@ -53,8 +52,6 @@ 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 {
 /// LatticeVal class - This class represents the different lattice values that
@@ -156,14 +153,6 @@ public:
     Val.setInt(forcedconstant);
     Val.setPointer(V);
   }
-
-  ValueLatticeElement toValueLattice() const {
-    if (isOverdefined())
-      return ValueLatticeElement::getOverdefined();
-    if (isConstant())
-      return ValueLatticeElement::get(getConstant());
-    return ValueLatticeElement();
-  }
 };
 } // end anonymous namespace.
 
@@ -180,8 +169,6 @@ 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.
@@ -303,15 +290,10 @@ public:
     return StructValues;
   }
 
-  ValueLatticeElement getLatticeValueFor(Value *V) {
-    if (ParamState.count(V) == 0) {
-      DenseMap<Value *, LatticeVal>::const_iterator I = ValueState.find(V);
-      assert(I != ValueState.end() &&
-             "V not found in ValueState nor Paramstate map!");
-      ParamState[V] = I->second.toValueLattice();
-    }
-
-    return ParamState[V];
+  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.
@@ -444,15 +426,6 @@ private:
     return LV;
   }
 
-  ValueLatticeElement &getParamState(Value *V) {
-    assert(!V->getType()->isStructTy() && "Should use getStructValueState");
-
-    if (ParamState.count(V) == 0)
-      ParamState[V] = getValueState(V).toValueLattice();
-
-    return ParamState[V];
-  }
-
   /// 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.
@@ -1189,9 +1162,6 @@ CallOverdefined:
           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));
       }
     }
@@ -1587,44 +1557,6 @@ bool SCCPSolver::ResolvedUndefsIn(Function &F) {
   return false;
 }
 
-static bool tryToReplaceWithConstantRange(SCCPSolver &Solver, Value *V) {
-  bool Changed = false;
-  if (!V->getType()->isIntegerTy())
-    return 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 &Use : V->uses()) {
-    auto *Icmp = dyn_cast<ICmpInst>(Use.getUser());
-    if (!Icmp)
-      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()) {
@@ -1641,19 +1573,10 @@ 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');
@@ -1893,17 +1816,12 @@ static bool runIPSCCP(Module &M, const DataLayout &DL,
     if (F.isDeclaration())
       continue;
 
-    if (Solver.isBlockExecutable(&F.front())) {
+    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);