Hello, I've started using boost::proto "prototype" to leverage the kernel code of my expression templates based library and I wanted to know how the followign can be done. Let's say such a statement is made : matrix<float> a,b,c,r; r = (a/b)+a+mul(b,c); using Proto i was able to turn this into a SIMD aware code that use SSE2 or Altivec (dependign on the platform) to operate. However, in Altivec, the sub-expression a+mul(b,c) can be mapped to a single, 3-ary vec_madd function that efficiently performs the mul-add operations. This replacement leads to a 80-90% incrase of performacnes compared to chaining mul and add. My question is : how can I use proto to detect such pattern (madd is an example, there is a lot of such pattern in SIMD code) and build a new expression in which the a+mul(b,c) expression is replaced by the madd(a,b,c) expression ? Thanks in advance. PS : if this proto related question doesn't fit here, can someone redirect me to the correct list or people ?