How to generate IR for declare SIMD functions?

I am not able to generate IR for SIMD function, only scalar definition of function is generated. I am using following code in C.

#pragma omp declare simd
int min(int a, int b)
return a < b ? a : b;

I compiled the code as follows: $ clang -fopenmp-simd -S -emit-llvm file_name.c -o file_name.ll