Compiler optimizations for vector instructions

摘要

An optimizing compiler includes a vector optimization mechanism that optimizes vector instructions by eliminating one or more vector element reverse operations. The compiler can generate code that includes multiple vector element reverse operations that are inserted by the compiler to account for a mismatch between the endian bias of the instruction and the endian preference indicated by the programmer or programming environment. The compiler then analyzes the code and reduces the number of vector element reverse operations to improve the run-time performance of the code.

主权项

1. A computer-implemented method executed by at least one processor for processing a plurality of instructions in a computer program, the method comprising:
providing a computer program including a plurality of instructions that includes at least one vector operation; and processing the plurality of instructions to eliminate at least one vector element reverse operation from the computer program to enhance run-time performance of the computer program by:
recording characteristics of vector instructions and forming subgraphs of related instructions by analyzing def-use and use-def chains for the computer program in a first pass;determining whether any of the subgraphs cannot be optimized in a second pass;identifying a computation in the computer program where all operations performed on input vectors are single instruction multiple data (SIMD) instructions and marking for removal at least one vector element reverse operation that corresponds to the computation in a third pass; anddeleting in a fourth pass the at least one vector element reverse operation marked for removal in the third pass.