Abstract: It will cost several years to design and implement a new product level compiler. Designing and implementing based on an already-issued product level compiler are the main approach to develop a compiler for a new architecture.GNU compiler collection (GCC) supports multiple high level languages and multiple platforms, and its internal documents and source code are open. Based on the Spare backend of GCC,we implemented the description of four-way doublcprecision short vector registers which support four-way doublcprecision SIMD instructions. In this process, we defined a new target machine, expanded a new vector mode, defined a new class of register constraints, provided the descriptions of four-way doubl}precision short vector registers,designed the machine descriptions of the four-way double-precision SIMD instructions. For the builtin functions for this kind of SIMD instructions, our GCC can produce correct SIMD instructions using such kind of vector registers.

Key words: GCC backend, Four-way double precision, Vector registers