Include optional subclass flags, such as inbounds, nsw, etc., in the

Constant uniquing tables. This allows distinct ConstantExpr objects
with the same operation and different flags.

Even though a ConstantExpr "a + b" is either always overflowing or
never overflowing (due to being a ConstantExpr), it's still necessary
to be able to represent it both with and without overflow flags at
the same time within the IR, because the safety of the flag may
depend on the context of the use. If the constant really does overflow,
it wouldn't ever be safe to use with the flag set, however the use
may be in code that is never actually executed.

This also makes it possible to merge all the flags tests into a single test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80998 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 106 insertions, 47 deletions

diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 37efafc9b2..a5b4f28968 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -632,21 +632,13 @@ Constant* ConstantVector::get(Constant* const* Vals, unsigned NumVals) {
 }
 
 Constant* ConstantExpr::getNSWAdd(Constant* C1, Constant* C2) {
-  Constant *C = getAdd(C1, C2);
-  // Set nsw attribute, assuming constant folding didn't eliminate the
-  // Add.
-  if (AddOperator *Add = dyn_cast<AddOperator>(C))
-    Add->setHasNoSignedWrap(true);
-  return C;
+  return getTy(C1->getType(), Instruction::Add, C1, C2,
+               OverflowingBinaryOperator::NoSignedWrap);
 }
 
 Constant* ConstantExpr::getExactSDiv(Constant* C1, Constant* C2) {
-  Constant *C = getSDiv(C1, C2);
-  // Set exact attribute, assuming constant folding didn't eliminate the
-  // SDiv.
-  if (SDivOperator *SDiv = dyn_cast<SDivOperator>(C))
-    SDiv->setIsExact(true);
-  return C;
+  return getTy(C1->getType(), Instruction::SDiv, C1, C2,
+               SDivOperator::IsExact);
 }
 
 // Utility function for determining if a ConstantExpr is a CastOp or not. This
@@ -729,15 +721,19 @@ ConstantExpr::getWithOperandReplaced(unsigned OpNo, Constant *Op) const {
     for (unsigned i = 1, e = getNumOperands(); i != e; ++i)
       Ops[i-1] = getOperand(i);
     if (OpNo == 0)
-      return ConstantExpr::getGetElementPtr(Op, &Ops[0], Ops.size());
+      return cast<GEPOperator>(this)->isInBounds() ?
+        ConstantExpr::getInBoundsGetElementPtr(Op, &Ops[0], Ops.size()) :
+        ConstantExpr::getGetElementPtr(Op, &Ops[0], Ops.size());
     Ops[OpNo-1] = Op;
-    return ConstantExpr::getGetElementPtr(getOperand(0), &Ops[0], Ops.size());
+    return cast<GEPOperator>(this)->isInBounds() ?
+      ConstantExpr::getInBoundsGetElementPtr(getOperand(0), &Ops[0], Ops.size()) :
+      ConstantExpr::getGetElementPtr(getOperand(0), &Ops[0], Ops.size());
   }
   default:
     assert(getNumOperands() == 2 && "Must be binary operator?");
     Op0 = (OpNo == 0) ? Op : getOperand(0);
     Op1 = (OpNo == 1) ? Op : getOperand(1);
-    return ConstantExpr::get(getOpcode(), Op0, Op1);
+    return ConstantExpr::get(getOpcode(), Op0, Op1, SubclassData);
   }
 }
 
@@ -779,13 +775,15 @@ getWithOperands(Constant* const *Ops, unsigned NumOps) const {
   case Instruction::ShuffleVector:
     return ConstantExpr::getShuffleVector(Ops[0], Ops[1], Ops[2]);
   case Instruction::GetElementPtr:
-    return ConstantExpr::getGetElementPtr(Ops[0], &Ops[1], NumOps-1);
+    return cast<GEPOperator>(this)->isInBounds() ?
+      ConstantExpr::getInBoundsGetElementPtr(Ops[0], &Ops[1], NumOps-1) :
+      ConstantExpr::getGetElementPtr(Ops[0], &Ops[1], NumOps-1);
   case Instruction::ICmp:
   case Instruction::FCmp:
     return ConstantExpr::getCompare(getPredicate(), Ops[0], Ops[1]);
   default:
     assert(getNumOperands() == 2 && "Must be binary operator?");
-    return ConstantExpr::get(getOpcode(), Ops[0], Ops[1]);
+    return ConstantExpr::get(getOpcode(), Ops[0], Ops[1], SubclassData);
   }
 }
 
@@ -1031,8 +1029,9 @@ static ExprMapKeyType getValType(ConstantExpr *CE) {
   Operands.reserve(CE->getNumOperands());
   for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
     Operands.push_back(cast<Constant>(CE->getOperand(i)));
-  return ExprMapKeyType(CE->getOpcode(), Operands, 
+  return ExprMapKeyType(CE->getOpcode(), Operands,
       CE->isCompare() ? CE->getPredicate() : 0,
+      CE->getRawSubclassOptionalData(),
       CE->hasIndices() ?
         CE->getIndices() : SmallVector<unsigned, 4>());
 }
@@ -1280,7 +1279,8 @@ Constant *ConstantExpr::getBitCast(Constant *C, const Type *DstTy) {
 }
 
 Constant *ConstantExpr::getTy(const Type *ReqTy, unsigned Opcode,
-                              Constant *C1, Constant *C2) {
+                              Constant *C1, Constant *C2,
+                              unsigned Flags) {
   // Check the operands for consistency first
   assert(Opcode >= Instruction::BinaryOpsBegin &&
          Opcode <  Instruction::BinaryOpsEnd   &&
@@ -1294,7 +1294,7 @@ Constant *ConstantExpr::getTy(const Type *ReqTy, unsigned Opcode,
       return FC;          // Fold a few common cases...
 
   std::vector<Constant*> argVec(1, C1); argVec.push_back(C2);
-  ExprMapKeyType Key(Opcode, argVec);
+  ExprMapKeyType Key(Opcode, argVec, 0, Flags);
   
   LLVMContextImpl *pImpl = ReqTy->getContext().pImpl;
   
@@ -1322,7 +1322,8 @@ Constant *ConstantExpr::getCompareTy(unsigned short predicate,
   }
 }
 
-Constant *ConstantExpr::get(unsigned Opcode, Constant *C1, Constant *C2) {
+Constant *ConstantExpr::get(unsigned Opcode, Constant *C1, Constant *C2,
+                            unsigned Flags) {
   // API compatibility: Adjust integer opcodes to floating-point opcodes.
   if (C1->getType()->isFPOrFPVector()) {
     if (Opcode == Instruction::Add) Opcode = Instruction::FAdd;
@@ -1387,7 +1388,7 @@ Constant *ConstantExpr::get(unsigned Opcode, Constant *C1, Constant *C2) {
   }
 #endif
 
-  return getTy(C1->getType(), Opcode, C1, C2);
+  return getTy(C1->getType(), Opcode, C1, C2, Flags);
 }
 
 Constant* ConstantExpr::getSizeOf(const Type* Ty) {
@@ -1481,6 +1482,36 @@ Constant *ConstantExpr::getGetElementPtrTy(const Type *ReqTy, Constant *C,
   return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
 }
 
+Constant *ConstantExpr::getInBoundsGetElementPtrTy(const Type *ReqTy,
+                                                   Constant *C,
+                                                   Value* const *Idxs,
+                                                   unsigned NumIdx) {
+  assert(GetElementPtrInst::getIndexedType(C->getType(), Idxs,
+                                           Idxs+NumIdx) ==
+         cast<PointerType>(ReqTy)->getElementType() &&
+         "GEP indices invalid!");
+
+  if (Constant *FC = ConstantFoldGetElementPtr(
+                              ReqTy->getContext(), C, (Constant**)Idxs, NumIdx))
+    return FC;          // Fold a few common cases...
+
+  assert(isa<PointerType>(C->getType()) &&
+         "Non-pointer type for constant GetElementPtr expression");
+  // Look up the constant in the table first to ensure uniqueness
+  std::vector<Constant*> ArgVec;
+  ArgVec.reserve(NumIdx+1);
+  ArgVec.push_back(C);
+  for (unsigned i = 0; i != NumIdx; ++i)
+    ArgVec.push_back(cast<Constant>(Idxs[i]));
+  const ExprMapKeyType Key(Instruction::GetElementPtr, ArgVec, 0,
+                           GEPOperator::IsInBounds);
+
+  LLVMContextImpl *pImpl = ReqTy->getContext().pImpl;
+
+  // Implicitly locked.
+  return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
+}
+
 Constant *ConstantExpr::getGetElementPtr(Constant *C, Value* const *Idxs,
                                          unsigned NumIdx) {
   // Get the result type of the getelementptr!
@@ -1494,12 +1525,12 @@ Constant *ConstantExpr::getGetElementPtr(Constant *C, Value* const *Idxs,
 Constant *ConstantExpr::getInBoundsGetElementPtr(Constant *C,
                                                  Value* const *Idxs,
                                                  unsigned NumIdx) {
-  Constant *Result = getGetElementPtr(C, Idxs, NumIdx);
-  // Set in bounds attribute, assuming constant folding didn't eliminate the
-  // GEP.
-  if (GEPOperator *GEP = dyn_cast<GEPOperator>(Result))
-    GEP->setIsInBounds(true);
-  return Result;
+  // Get the result type of the getelementptr!
+  const Type *Ty = 
+    GetElementPtrInst::getIndexedType(C->getType(), Idxs, Idxs+NumIdx);
+  assert(Ty && "GEP indices invalid!");
+  unsigned As = cast<PointerType>(C->getType())->getAddressSpace();
+  return getInBoundsGetElementPtrTy(PointerType::get(Ty, As), C, Idxs, NumIdx);
 }
 
 Constant *ConstantExpr::getGetElementPtr(Constant *C, Constant* const *Idxs,
@@ -2104,7 +2135,7 @@ void ConstantExpr::replaceUsesOfWithOnConstant(Value *From, Value *ToV,
     Constant *C2 = getOperand(1);
     if (C1 == From) C1 = To;
     if (C2 == From) C2 = To;
-    Replacement = ConstantExpr::get(getOpcode(), C1, C2);
+    Replacement = ConstantExpr::get(getOpcode(), C1, C2, SubclassData);
   } else {
     llvm_unreachable("Unknown ConstantExpr type!");
     return;
diff --git a/lib/VMCore/ConstantsContext.h b/lib/VMCore/ConstantsContext.h
index 718470aff4..16975b3611 100644
--- a/lib/VMCore/ConstantsContext.h
+++ b/lib/VMCore/ConstantsContext.h
@@ -53,10 +53,12 @@ public:
   void *operator new(size_t s) {
     return User::operator new(s, 2);
   }
-  BinaryConstantExpr(unsigned Opcode, Constant *C1, Constant *C2)
+  BinaryConstantExpr(unsigned Opcode, Constant *C1, Constant *C2,
+                     unsigned Flags)
     : ConstantExpr(C1->getType(), Opcode, &Op<0>(), 2) {
     Op<0>() = C1;
     Op<1>() = C2;
+    SubclassOptionalData = Flags;
   }
   /// Transparently provide more efficient getOperand methods.
   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
@@ -206,9 +208,12 @@ class GetElementPtrConstantExpr : public ConstantExpr {
 public:
   static GetElementPtrConstantExpr *Create(Constant *C,
                                            const std::vector<Constant*>&IdxList,
-                                           const Type *DestTy) {
-    return
+                                           const Type *DestTy,
+                                           unsigned Flags) {
+    GetElementPtrConstantExpr *Result =
       new(IdxList.size() + 1) GetElementPtrConstantExpr(C, IdxList, DestTy);
+    Result->SubclassOptionalData = Flags;
+    return Result;
   }
   /// Transparently provide more efficient getOperand methods.
   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
@@ -291,26 +296,32 @@ struct ExprMapKeyType {
 
   ExprMapKeyType(unsigned opc,
       const std::vector<Constant*> &ops,
-      unsigned short pred = 0,
+      unsigned short flags = 0,
+      unsigned short optionalflags = 0,
       const IndexList &inds = IndexList())
-        : opcode(opc), predicate(pred), operands(ops), indices(inds) {}
-  uint16_t opcode;
-  uint16_t predicate;
+        : opcode(opc), subclassoptionaldata(optionalflags), subclassdata(flags),
+        operands(ops), indices(inds) {}
+  uint8_t opcode;
+  uint8_t subclassoptionaldata;
+  uint16_t subclassdata;
   std::vector<Constant*> operands;
   IndexList indices;
   bool operator==(const ExprMapKeyType& that) const {
     return this->opcode == that.opcode &&
-           this->predicate == that.predicate &&
+           this->subclassdata == that.subclassdata &&
+           this->subclassoptionaldata == that.subclassoptionaldata &&
            this->operands == that.operands &&
            this->indices == that.indices;
   }
   bool operator<(const ExprMapKeyType & that) const {
-    return this->opcode < that.opcode ||
-      (this->opcode == that.opcode && this->predicate < that.predicate) ||
-      (this->opcode == that.opcode && this->predicate == that.predicate &&
-       this->operands < that.operands) ||
-      (this->opcode == that.opcode && this->predicate == that.predicate &&
-       this->operands == that.operands && this->indices < that.indices);
+    if (this->opcode != that.opcode) return this->opcode < that.opcode;
+    if (this->operands != that.operands) return this->operands < that.operands;
+    if (this->subclassdata != that.subclassdata)
+      return this->subclassdata < that.subclassdata;
+    if (this->subclassoptionaldata != that.subclassoptionaldata)
+      return this->subclassoptionaldata < that.subclassoptionaldata;
+    if (this->indices != that.indices) return this->indices < that.indices;
+    return false;
   }
 
   bool operator!=(const ExprMapKeyType& that) const {
@@ -354,7 +365,8 @@ struct ConstantCreator<ConstantExpr, Type, ExprMapKeyType> {
       return new UnaryConstantExpr(V.opcode, V.operands[0], Ty);
     if ((V.opcode >= Instruction::BinaryOpsBegin &&
          V.opcode < Instruction::BinaryOpsEnd))
-      return new BinaryConstantExpr(V.opcode, V.operands[0], V.operands[1]);
+      return new BinaryConstantExpr(V.opcode, V.operands[0], V.operands[1],
+                                    V.subclassoptionaldata);
     if (V.opcode == Instruction::Select)
       return new SelectConstantExpr(V.operands[0], V.operands[1], 
                                     V.operands[2]);
@@ -373,17 +385,18 @@ struct ConstantCreator<ConstantExpr, Type, ExprMapKeyType> {
       return new ExtractValueConstantExpr(V.operands[0], V.indices, Ty);
     if (V.opcode == Instruction::GetElementPtr) {
       std::vector<Constant*> IdxList(V.operands.begin()+1, V.operands.end());
-      return GetElementPtrConstantExpr::Create(V.operands[0], IdxList, Ty);
+      return GetElementPtrConstantExpr::Create(V.operands[0], IdxList, Ty,
+                                               V.subclassoptionaldata);
     }
 
     // The compare instructions are weird. We have to encode the predicate
     // value and it is combined with the instruction opcode by multiplying
     // the opcode by one hundred. We must decode this to get the predicate.
     if (V.opcode == Instruction::ICmp)
-      return new CompareConstantExpr(Ty, Instruction::ICmp, V.predicate, 
+      return new CompareConstantExpr(Ty, Instruction::ICmp, V.subclassdata,
                                      V.operands[0], V.operands[1]);
     if (V.opcode == Instruction::FCmp) 
-      return new CompareConstantExpr(Ty, Instruction::FCmp, V.predicate, 
+      return new CompareConstantExpr(Ty, Instruction::FCmp, V.subclassdata,
                                      V.operands[0], V.operands[1]);
     llvm_unreachable("Invalid ConstantExpr!");
     return 0;
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index 2d4ab55721..9d8e0477ee 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -1171,6 +1171,9 @@ bool GetElementPtrInst::hasAllConstantIndices() const {
   return true;
 }
 
+void GetElementPtrInst::setIsInBounds(bool B) {
+  cast<GEPOperator>(this)->setIsInBounds(B);
+}
 
 //===----------------------------------------------------------------------===//
 //                           ExtractElementInst Implementation
@@ -1716,6 +1719,18 @@ bool BinaryOperator::swapOperands() {
   return false;
 }
 
+void BinaryOperator::setHasNoUnsignedWrap(bool b) {
+  cast<OverflowingBinaryOperator>(this)->setHasNoUnsignedWrap(b);
+}
+
+void BinaryOperator::setHasNoSignedWrap(bool b) {
+  cast<OverflowingBinaryOperator>(this)->setHasNoSignedWrap(b);
+}
+
+void BinaryOperator::setIsExact(bool b) {
+  cast<SDivOperator>(this)->setIsExact(b);
+}
+
 //===----------------------------------------------------------------------===//
 //                                CastInst Class
 //===----------------------------------------------------------------------===//