vtkAssume.h

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/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkAssume.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
#ifndef vtkAssume_h
#define vtkAssume_h

#include "vtkConfigure.h"

#include <cassert>

#define VTK_ASSUME(cond) \
  do { \
  const bool c = cond; \
  assert("Bad assumption in VTK_ASSUME: " #cond && c); \
  VTK_ASSUME_IMPL(c); \
  (void)c; /* Prevents unused var warnings */ \
  } while (false) /* do-while prevents extra semicolon warnings */

// VTK_ASSUME_IMPL is compiler-specific:
#if defined(VTK_COMPILER_MSVC) || defined(VTK_COMPILER_ICC)
# define VTK_ASSUME_IMPL(cond) __assume(cond)
#elif defined(VTK_COMPILER_GCC) && VTK_COMPILER_GCC_VERSION >= 40500
// Added in 4.5.0:
# define VTK_ASSUME_IMPL(cond) if (!(cond)) __builtin_unreachable()
#elif defined(VTK_COMPILER_CLANG)
# define VTK_ASSUME_IMPL(cond) if (!(cond)) __builtin_unreachable()
#else
# define VTK_ASSUME_IMPL(cond) do {} while (false) /* no-op */
#endif

#endif // vtkAssume_h
// VTK-HeaderTest-Exclude: vtkAssume.h