What is the purpose of using multiple “arch” flags in Nvidia's NVCC compiler?

Question

I\'ve recently gotten my head around how NVCC compiles CUDA device code for different compute architectures.

From my understanding, when using NVCC\'s -gencode optio

Answer 1

The purpose of multiple -arch flags is to use the __CUDA_ARCH__ macro for conditional compilation (ie, using #ifdef) of differently-optimized code paths.

See here: http://docs.nvidia.com/cuda/cuda-compiler-driver-nvcc/index.html#virtual-architecture-identification-macro