The recent proliferation of the Single Instruction Multiple Data (SIMD) model has lead to a wide variety of implementations. These have been incorporated into many platforms, from gaming machines and DSPs to general purpose architectures. In this paper we present an automatic vectorizer as implemented in GCC, the most multi-targetable compiler available today. We discuss the considerations involved in developing a multi-platform vectorization technology, and demonstrate how our vectorization scheme is suited to a variety of SIMD architectures. Experiments on four different SIMD platforms demonstrate that our automatic vectorization scheme is able to efficiently support individual platforms, achieving significant speedups on key kernels.