Issues with omp simd

hello,

i am trying to optimize omp simd loop as follows

int main(int argc, char **argv)
{
const int size = 1000000;

float a[size], b[size],c[size];

#pragma omp simd
for (int i=0; i<size; ++i)
{
c[i]= a[i] + b[i];
}

return 0;
}

i run it using the following command;

g++ -O0 --std=c++14 -fopenmp-simd lab.cpp -Iinclude -S -o lab.s

when i compared it with code as follows without simd

int main(int argc, char **argv)
{
const int size = 1000000;

float a[size], b[size],c[size];

for (int i=0; i<size; ++i)
{
c[i]= a[i] + b[i];
}

return 0;
}

using following command

g++ -O0 --std=c++14 lab.cpp -Iinclude -S -o lab.s

I am getting the same assembly. Why is that so? why not omp simd is more efficient?

Please help