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.x
  • Fortran
  • Intel® Composer XE
  • Compilador Fortran Intel®+
  • Composer XE Fortran Intel®
  • Composer XE Visual Fortran Intel®
  • Intel® Fortran Studio XE
  • Intel® Parallel Studio XE
  • error
  • vectorization diagnostic messages
  • alignment
  • Ferramentas de desenvolvimento
  • Vetorização
  • 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. 

  • Desenvolvedores
  • Professores
  • Estudantes
  • C/C++
  • Fortran
  • Avançado
  • Intermediário
  • Compilador C++ Intel®
  • Compilador Fortran Intel®+
  • alignment
  • structures
  • performance
  • Otimização
  • Assine o alignment