alignment

Diagnostic 15134: vectorization support: reference xxxx has unaligned access (Fortran)

Cause:

The vectorizer cannot safely use aligned loads or stores for this data access, either because the data are not aligned to an n-byte boundary in memory, or because the compiler does not know the alignment. The compiler must use unaligned memory accesses, which may be less efficient. The value of n depends on the targeted instruction set and corresponds to the width of the vector instructions: 16 for Intel® SSE, 32 for Intel® AVX and 64 for Intel® AVX-512 instructions.

Example:

  • Apple OS X*
  • Linux*
  • Microsoft Windows* (XP, Vista, 7)
  • Microsoft Windows* 8
  • Fortran
  • Intel® Composer XE
  • Intel® Fortran Compiler
  • Intel® Fortran Composer XE
  • Intel® Visual Fortran Composer XE
  • Intel® Fortran Studio XE
  • Intel® Parallel Studio XE
  • error
  • vectorization diagnostic messages
  • alignment
  • Инструменты для разработки
  • Векторизация
  • Coding for Performance: Data alignment and structures

    This article collects the general knowledge and Best-Known-Methods (BKMs) for aligning of data within structures in order to achieve optimal performance. 

  • Разработчики
  • Профессорский состав
  • Студенты
  • C/C++
  • Fortran
  • Продвинутый
  • Средний
  • Intel® C++ Compiler
  • Intel® Fortran Compiler
  • alignment
  • structures
  • performance
  • Оптимизация
  • Intel ArBB Segregated Storage and Data Copies

    This article will answer the question when and how many copies occur for the inputs and outputs of an Intel ArBB function.
  • ПО WhatIf
  • SOA
  • webinar
  • bind
  • alignment
  • JIT
  • AOS
  • code tips
  • range
  • copy-in
  • copy-out
  • stride
  • pitch
  • memory mapping
  • call-operator
  • Оптимизация
  • Параллельные вычисления
  • Подписаться на alignment