Abstract: SIMD automatic vectorization is an important means to give full play to the computing power of processors and improve the performance of applications,but the existence of control flow brings great challenges to automatic vectorization.The traditional control flow quantization method relies on IF transformation technology,but this technology also brings the problem of low efficiency of code execution.Therefore,in order to alleviate this problem,a speculative vectorization method of control flow for SIMD is proposed.The method detects the predicate-related region in vector code,uses the cost model to guide the implementation of the speculative transformation for branch consistency in the region,and eliminates the useless predicate execution at runtime,thus eliminating the problem of low code efficiency caused by redundant computation.The work of this method is based on the current mainstream GCC10.3 compiler.The experiment selected the industry-recognized SPEC CPU 2006 test set topic and the TSVC test set of testing vectorization ability.The results showed that the performance of SPEC2006 test set 481 topic was improved by 10% after using this method.The acceleration ratio of typical TSVC_2 test cases can reach more than 20%.Experimental results on standard test sets show that this method can effectively improve the execution efficiency of GCC compiler’scontrol flow quantization code

Key words: SIMD, GCC, Control flow, Cost model, Speculative vectorization