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      1 //===--- APSIntType.cpp - Simple record of the type of APSInts ------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 #include "clang/StaticAnalyzer/Core/PathSensitive/APSIntType.h"
     11 
     12 using namespace clang;
     13 using namespace ento;
     14 
     15 APSIntType::RangeTestResultKind
     16 APSIntType::testInRange(const llvm::APSInt &Value,
     17                         bool AllowSignConversions) const {
     18 
     19   // Negative numbers cannot be losslessly converted to unsigned type.
     20   if (IsUnsigned && !AllowSignConversions &&
     21       Value.isSigned() && Value.isNegative())
     22     return RTR_Below;
     23 
     24   unsigned MinBits;
     25   if (AllowSignConversions) {
     26     if (Value.isSigned() && !IsUnsigned)
     27       MinBits = Value.getMinSignedBits();
     28     else
     29       MinBits = Value.getActiveBits();
     30 
     31   } else {
     32     // Signed integers can be converted to signed integers of the same width
     33     // or (if positive) unsigned integers with one fewer bit.
     34     // Unsigned integers can be converted to unsigned integers of the same width
     35     // or signed integers with one more bit.
     36     if (Value.isSigned())
     37       MinBits = Value.getMinSignedBits() - IsUnsigned;
     38     else
     39       MinBits = Value.getActiveBits() + !IsUnsigned;
     40   }
     41 
     42   if (MinBits <= BitWidth)
     43     return RTR_Within;
     44 
     45   if (Value.isSigned() && Value.isNegative())
     46     return RTR_Below;
     47   else
     48     return RTR_Above;
     49 }
     50