Abstract:

The general purpose processors support multicore parallelism on a chip and SIMD parallelism in each core. Although GCC complier makes use of the auto-vectorization for SIMD parallelism, the effects of autovectorization for OpenMP program is far from the expectation. Based on the implementation of the OpenMP compilation in GCC, we extend complier directives with data alignment attribute directive for OpenMP program. Our work enables GCC to make a more accurate estimation  on the alignment of data access, and optimizes the auto-vectorization in GCC.

Key words: data alignment attribute;compiler directives;auto-vectorization;GCC