gistfile1.cpp

#include <vector>

struct vec4 {
  float __attribute__((vector_size(16))) elts;
};

void putVec4(vec4 *out, const std::vector<float> &v) {
  *out = {{v[0], v[1], v[2], v[3]}};
}

/*
$ clang++ -DNDEBUG -O3 -std=c++11 -S ~/foo.cpp
__Z7putVec4P4vec4RKSt6vectorIfSaIfEE:   ## @_Z7putVec4P4vec4RKSt6vectorIfSaIfEE
	pushq	%rbp
	movq	%rsp, %rbp
	movq	(%rsi), %rax
	movups	(%rax), %xmm0
	movaps	%xmm0, (%rdi)
	popq	%rbp
	ret
*/