From 3892560680e244601e52080f448df75988d89663 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 10 Oct 2005 16:49:22 +0000
Subject: [PATCH] This function is now dead

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23684 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 110 ----------------------
 1 file changed, 110 deletions(-)

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 4ba509e0ef0..faeb440b4b4 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -576,116 +576,6 @@ SDOperand SelectionDAG::getRegister(unsigned RegNo, MVT::ValueType VT) {
   return SDOperand(Reg, 0);
 }
 
-/// MaskedValueIsZero - Return true if 'V & Mask' is known to be zero.  We use
-/// this predicate to simplify operations downstream.  V and Mask are known to
-/// be the same type.
-static bool MaskedValueIsZero(const SDOperand &Op, uint64_t Mask,
-                              const TargetLowering &TLI) {
-  unsigned SrcBits;
-  if (Mask == 0) return true;
-  
-  // If we know the result of a setcc has the top bits zero, use this info.
-  switch (Op.getOpcode()) {
-  case ISD::Constant:
-    return (cast<ConstantSDNode>(Op)->getValue() & Mask) == 0;
-    
-  case ISD::SETCC:
-    return ((Mask & 1) == 0) &&
-    TLI.getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult;
-    
-  case ISD::ZEXTLOAD:
-    SrcBits = MVT::getSizeInBits(cast<VTSDNode>(Op.getOperand(3))->getVT());
-    return (Mask & ((1ULL << SrcBits)-1)) == 0; // Returning only the zext bits.
-  case ISD::ZERO_EXTEND:
-    SrcBits = MVT::getSizeInBits(Op.getOperand(0).getValueType());
-    return MaskedValueIsZero(Op.getOperand(0),Mask & ((1ULL << SrcBits)-1),TLI);
-  case ISD::AssertZext:
-    SrcBits = MVT::getSizeInBits(cast<VTSDNode>(Op.getOperand(1))->getVT());
-    return (Mask & ((1ULL << SrcBits)-1)) == 0; // Returning only the zext bits.
-  case ISD::AND:
-    // If either of the operands has zero bits, the result will too.
-    if (MaskedValueIsZero(Op.getOperand(1), Mask, TLI) ||
-        MaskedValueIsZero(Op.getOperand(0), Mask, TLI))
-      return true;
-
-    // (X & C1) & C2 == 0   iff   C1 & C2 == 0.
-    if (ConstantSDNode *AndRHS = dyn_cast<ConstantSDNode>(Op.getOperand(1)))
-      return MaskedValueIsZero(Op.getOperand(0),AndRHS->getValue() & Mask, TLI);
-    return false;
-  case ISD::OR:
-  case ISD::XOR:
-    return MaskedValueIsZero(Op.getOperand(0), Mask, TLI) &&
-           MaskedValueIsZero(Op.getOperand(1), Mask, TLI);
-  case ISD::SELECT:
-    return MaskedValueIsZero(Op.getOperand(1), Mask, TLI) &&
-           MaskedValueIsZero(Op.getOperand(2), Mask, TLI);
-  case ISD::SELECT_CC:
-    return MaskedValueIsZero(Op.getOperand(2), Mask, TLI) &&
-           MaskedValueIsZero(Op.getOperand(3), Mask, TLI);
-  case ISD::SRL:
-    // (ushr X, C1) & C2 == 0   iff  X & (C2 << C1) == 0
-    if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
-      uint64_t NewVal = Mask << ShAmt->getValue();
-      SrcBits = MVT::getSizeInBits(Op.getValueType());
-      if (SrcBits != 64) NewVal &= (1ULL << SrcBits)-1;
-      return MaskedValueIsZero(Op.getOperand(0), NewVal, TLI);
-    }
-    return false;
-  case ISD::SHL:
-    // (ushl X, C1) & C2 == 0   iff  X & (C2 >> C1) == 0
-    if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
-      uint64_t NewVal = Mask >> ShAmt->getValue();
-      return MaskedValueIsZero(Op.getOperand(0), NewVal, TLI);
-    }
-    return false;
-  case ISD::ADD:
-    // (add X, Y) & C == 0 iff (X&C)|(Y&C) == 0 and all bits are low bits.
-    if ((Mask&(Mask+1)) == 0) {  // All low bits
-      if (MaskedValueIsZero(Op.getOperand(0), Mask, TLI) &&
-          MaskedValueIsZero(Op.getOperand(1), Mask, TLI)) {
-        std::cerr << "MASK: ";
-        Op.getOperand(0).Val->dump();
-        std::cerr << " - ";
-        Op.getOperand(1).Val->dump();
-        std::cerr << "\n";
-        return true;
-      }
-    }
-    break;    
-  case ISD::SUB:
-    if (ConstantSDNode *CLHS = dyn_cast<ConstantSDNode>(Op.getOperand(0))) {
-      // We know that the top bits of C-X are clear if X contains less bits
-      // than C (i.e. no wrap-around can happen).  For example, 20-X is
-      // positive if we can prove that X is >= 0 and < 16.
-      unsigned Bits = MVT::getSizeInBits(CLHS->getValueType(0));
-      if ((CLHS->getValue() & (1 << (Bits-1))) == 0) {  // sign bit clear
-        unsigned NLZ = CountLeadingZeros_64(CLHS->getValue()+1);
-        uint64_t MaskV = (1ULL << (63-NLZ))-1;
-        if (MaskedValueIsZero(Op.getOperand(1), ~MaskV, TLI)) {
-          // High bits are clear this value is known to be >= C.
-          unsigned NLZ2 = CountLeadingZeros_64(CLHS->getValue());
-          if ((Mask & ((1ULL << (64-NLZ2))-1)) == 0)
-            return true;
-        }
-      }
-    }
-    break;
-  case ISD::CTTZ:
-  case ISD::CTLZ:
-  case ISD::CTPOP:
-    // Bit counting instructions can not set the high bits of the result
-    // register.  The max number of bits sets depends on the input.
-    return (Mask & (MVT::getSizeInBits(Op.getValueType())*2-1)) == 0;
-    
-    // TODO we could handle some SRA cases here.
-  default: break;
-  }
-  
-  return false;
-}
-
-
-
 SDOperand SelectionDAG::SimplifySetCC(MVT::ValueType VT, SDOperand N1,
                                       SDOperand N2, ISD::CondCode Cond) {
   // These setcc operations always fold.