X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FVMCore%2FConstantFold.cpp;h=ff4d897e54a8b945d1d49ff959a424f49452b943;hb=b5bd026a756d8650f2a94607c9b1dc34cf1c024a;hp=93cfccf1f5e672f7f06ecf02e9a4ef392de2f8bf;hpb=8373d38afddec4ade17f72088cb5eeb229e87238;p=oota-llvm.git

diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index 93cfccf1f5e..ff4d897e54a 100644
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -126,6 +126,7 @@ static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
     if (const VectorType *SrcTy = dyn_cast<VectorType>(V->getType())) {
       assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
              "Not cast between same sized vectors!");
+      SrcTy = NULL;
       // First, check for null.  Undef is already handled.
       if (isa<ConstantAggregateZero>(V))
         return Constant::getNullValue(DestTy);
@@ -133,6 +134,12 @@ static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
       if (ConstantVector *CV = dyn_cast<ConstantVector>(V))
         return BitCastConstantVector(CV, DestPTy);
     }
+
+    // Canonicalize scalar-to-vector bitcasts into vector-to-vector bitcasts
+    // This allows for other simplifications (although some of them
+    // can only be handled by Analysis/ConstantFolding.cpp).
+    if (isa<ConstantInt>(V) || isa<ConstantFP>(V))
+      return ConstantExpr::getBitCast(ConstantVector::get(&V, 1), DestPTy);
   }
   
   // Finally, implement bitcast folding now.   The code below doesn't handle
@@ -146,26 +153,20 @@ static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
       // Integral -> Integral. This is a no-op because the bit widths must
       // be the same. Consequently, we just fold to V.
       return V;
-    
-    if (DestTy->isFloatingPoint()) {
-      assert((DestTy == Type::DoubleTy || DestTy == Type::FloatTy) && 
-             "Unknown FP type!");
-      return ConstantFP::get(APFloat(CI->getValue()));
-    }
+
+    if (DestTy->isFloatingPoint())
+      return ConstantFP::get(APFloat(CI->getValue(),
+                                     DestTy != Type::PPC_FP128Ty));
+
     // Otherwise, can't fold this (vector?)
     return 0;
   }
-  
+
   // Handle ConstantFP input.
-  if (const ConstantFP *FP = dyn_cast<ConstantFP>(V)) {
+  if (const ConstantFP *FP = dyn_cast<ConstantFP>(V))
     // FP -> Integral.
-    if (DestTy == Type::Int32Ty) {
-      return ConstantInt::get(FP->getValueAPF().convertToAPInt());
-    } else {
-      assert(DestTy == Type::Int64Ty && "only support f32/f64 for now!");
-      return ConstantInt::get(FP->getValueAPF().convertToAPInt());
-    }
-  }
+    return ConstantInt::get(FP->getValueAPF().bitcastToAPInt());
+
   return 0;
 }
 
@@ -213,13 +214,14 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
   case Instruction::FPTrunc:
   case Instruction::FPExt:
     if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
+      bool ignored;
       APFloat Val = FPC->getValueAPF();
       Val.convert(DestTy == Type::FloatTy ? APFloat::IEEEsingle :
                   DestTy == Type::DoubleTy ? APFloat::IEEEdouble :
                   DestTy == Type::X86_FP80Ty ? APFloat::x87DoubleExtended :
                   DestTy == Type::FP128Ty ? APFloat::IEEEquad :
                   APFloat::Bogus,
-                  APFloat::rmNearestTiesToEven);
+                  APFloat::rmNearestTiesToEven, &ignored);
       return ConstantFP::get(Val);
     }
     return 0; // Can't fold.
@@ -227,10 +229,11 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
   case Instruction::FPToSI:
     if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
       const APFloat &V = FPC->getValueAPF();
+      bool ignored;
       uint64_t x[2]; 
       uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
       (void) V.convertToInteger(x, DestBitWidth, opc==Instruction::FPToSI,
-                                APFloat::rmTowardZero);
+                                APFloat::rmTowardZero, &ignored);
       APInt Val(DestBitWidth, 2, x);
       return ConstantInt::get(Val);
     }
@@ -415,24 +418,25 @@ Constant *llvm::ConstantFoldShuffleVectorInstruction(const Constant *V1,
                                                      const Constant *Mask) {
   // Undefined shuffle mask -> undefined value.
   if (isa<UndefValue>(Mask)) return UndefValue::get(V1->getType());
-  
-  unsigned NumElts = cast<VectorType>(V1->getType())->getNumElements();
+
+  unsigned MaskNumElts = cast<VectorType>(Mask->getType())->getNumElements();
+  unsigned SrcNumElts = cast<VectorType>(V1->getType())->getNumElements();
   const Type *EltTy = cast<VectorType>(V1->getType())->getElementType();
-  
+
   // Loop over the shuffle mask, evaluating each element.
   SmallVector<Constant*, 32> Result;
-  for (unsigned i = 0; i != NumElts; ++i) {
+  for (unsigned i = 0; i != MaskNumElts; ++i) {
     Constant *InElt = GetVectorElement(Mask, i);
     if (InElt == 0) return 0;
-    
+
     if (isa<UndefValue>(InElt))
       InElt = UndefValue::get(EltTy);
     else if (ConstantInt *CI = dyn_cast<ConstantInt>(InElt)) {
       unsigned Elt = CI->getZExtValue();
-      if (Elt >= NumElts*2)
+      if (Elt >= SrcNumElts*2)
         InElt = UndefValue::get(EltTy);
-      else if (Elt >= NumElts)
-        InElt = GetVectorElement(V2, Elt-NumElts);
+      else if (Elt >= SrcNumElts)
+        InElt = GetVectorElement(V2, Elt - SrcNumElts);
       else
         InElt = GetVectorElement(V1, Elt);
       if (InElt == 0) return 0;
@@ -442,7 +446,7 @@ Constant *llvm::ConstantFoldShuffleVectorInstruction(const Constant *V1,
     }
     Result.push_back(InElt);
   }
-  
+
   return ConstantVector::get(&Result[0], Result.size());
 }
 
@@ -645,11 +649,15 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
     case Instruction::SDiv:
       if (CI2->equalsInt(1))
         return const_cast<Constant*>(C1);                     // X / 1 == X
+      if (CI2->equalsInt(0))
+        return UndefValue::get(CI2->getType());               // X / 0 == undef
       break;
     case Instruction::URem:
     case Instruction::SRem:
       if (CI2->equalsInt(1))
         return Constant::getNullValue(CI2->getType());        // X % 1 == 0
+      if (CI2->equalsInt(0))
+        return UndefValue::get(CI2->getType());               // X % 0 == undef
       break;
     case Instruction::And:
       if (CI2->isZero()) return const_cast<Constant*>(C2);    // X & 0 == 0
@@ -723,24 +731,20 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
       case Instruction::Mul:     
         return ConstantInt::get(C1V * C2V);
       case Instruction::UDiv:
-        if (CI2->isNullValue())                  
-          return 0;        // X / 0 -> can't fold
+        assert(!CI2->isNullValue() && "Div by zero handled above");
         return ConstantInt::get(C1V.udiv(C2V));
       case Instruction::SDiv:
-        if (CI2->isNullValue()) 
-          return 0;        // X / 0 -> can't fold
+        assert(!CI2->isNullValue() && "Div by zero handled above");
         if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
-          return 0;        // MIN_INT / -1 -> overflow
+          return UndefValue::get(CI1->getType());   // MIN_INT / -1 -> undef
         return ConstantInt::get(C1V.sdiv(C2V));
       case Instruction::URem:
-        if (C2->isNullValue()) 
-          return 0;        // X / 0 -> can't fold
+        assert(!CI2->isNullValue() && "Div by zero handled above");
         return ConstantInt::get(C1V.urem(C2V));
-      case Instruction::SRem:    
-        if (CI2->isNullValue()) 
-          return 0;        // X % 0 -> can't fold
+      case Instruction::SRem:
+        assert(!CI2->isNullValue() && "Div by zero handled above");
         if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
-          return 0;        // MIN_INT % -1 -> overflow
+          return UndefValue::get(CI1->getType());   // MIN_INT % -1 -> undef
         return ConstantInt::get(C1V.srem(C2V));
       case Instruction::And:
         return ConstantInt::get(C1V & C2V);
@@ -792,16 +796,6 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
         (void)C3V.divide(C2V, APFloat::rmNearestTiesToEven);
         return ConstantFP::get(C3V);
       case Instruction::FRem:
-        if (C2V.isZero()) {
-          // IEEE 754, Section 7.1, #5
-          if (CFP1->getType() == Type::DoubleTy)
-            return ConstantFP::get(APFloat(std::numeric_limits<double>::
-                                           quiet_NaN()));
-          if (CFP1->getType() == Type::FloatTy)
-            return ConstantFP::get(APFloat(std::numeric_limits<float>::
-                                           quiet_NaN()));
-          break;
-        }
         (void)C3V.mod(C2V, APFloat::rmNearestTiesToEven);
         return ConstantFP::get(C3V);
       }