Cannot vectorize array notations

Cannot vectorize array notations

Hi all,I have vectorization problems and I really need your help.Here are the vectorization reports for each array notation in the code bellow: -Array Notation(1) : Vectorized -Array Notation(2) : Subscript too complex -Array Notation(3) : Existence of vector dependence -Array Notation(4) : Subscript too complex -Array Notatino(5) : Subscript too complex -Array Notation(6) : Existence of vector dependenceI tried using "restrict" on the pointers(i.e. int* restric p_p_data_), but didn't work.Is there any problem I'm missing?Thanks in advance![CPU Info] -Core2 Quad Q9400[OS Info] -WinXP Pro SP3[Compiler Info] -Composer XE 2011 Update7, Package ID:w_ccompxe_2011.7.258

class SomeClass {

  SomeClass();

  ~SomeClass();

  void Init();

  void PreProcess();

  void Process();

  __declspec (vector) int GetDiff(int sub, int add) {

    return (add - sub);

  };

  const byte* add_point_;

  const byte* subtract_point_;

  std::vector y_data_;

  std::vector x_data_;

  std::vector processed_data_;

  int* p_y_data_;

  int* p_x_data_;

  int* p_p_data_;

};
void Init() {

  x_data_.resize(5000);

  y_data_.resize(5000);

  processed_data_.resize(5000);

  p_x_data_ = &x_data_.front();

  p_y_data_ = &y_data_.front();

  p_p_data_ = &processed_data_.front();

  return;

}
void PreProcess() {

  int x_size = 5000;

  add_point_ = image_->base_address();

  subtract_point_ = add_point_;

  // Array Notation(1)

  p_y_data_[0:x_size] = add_point_[0:x_size];

  for (int y = 0; y < 4; y++) {

    // Array Notation(2)

    p_y_data_[0:x_size] += add_point_[0:x_size];

  }

  return;

}
void Process() {

  int x_size = 5000;

  // Array Notation(3)

  p_y_data_[0:x_size] += GetDiff(subtract_point_[0:x_size], add_point_[0:x_size]);

  // Array Notation(4)

  p_x_data_[0:x_size] = p_y_data_[0:x_size];

  x_size--;

  for (int x = 1; x < 4; x++) {

    // Array Notation(5)

    p_x_data_[0:x_size] += p_y_data_[x:x_size];

    x_size--;

  }

  x_size -= 4;

  // Array Notation(6)

  p_p_data_[0:x_size] = GetDiff(p_x_data_[0:x_size], p_x_data_[settings_->df.block_width:x_size]);

  return;

}

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What compiler are you use?

Your compiler options would need to include -ansi-alias -restrict , and you have left your restrict out of your source code (restrict or __restrict may work, but not __restrict__ with the relatively old compiler). It's hard to guess what you have done; an actual example with your compile command would go a long way. If you are depending on the new gcc compatibility, that is an option for ICL 13.0.

Hi Maycon Oliveira!Thank you for your reply.I'm using intel composer xe on Visual Studio 2005.

Hi Timp!Thank you for your reply.Vectocization worked with "Qansi-alias" compiler option.But, I thought that the "restrict" qualifier and the "Qrestrict" compiler option were enough to remove the vector dependency of pointers.Using "Qansi-alias" I have to worry about pointers aliasing on other part of the total source code...I also tried "restrict" instead of "__restrict" but didn't work.Maybe, "restict" shouldn't be used on members of a class?

Best Reply

ansi-alias is needed so as to assert that the (non-integer) data contained in a doesn't alias with the book-keeping data. I suppose it would be particularly inadvisable to expect a compiler to accept code which violates the standard in such a case, but Windows applications do frequently have such expectations.
restrict would be used to assert non-aliasing among data regions defined separately outside the local scope and accessed by pointers (C style); by extension, it might apply to reference. As restrict still is not formally defined for C++, you are correct that it may not necessarily be meaningful in class context.

Declaring restrict pointers inside my function worked and finally vectorization sucessed!Thank you so much for your help!!!

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