Does gcc hoist memory-reference based loop invariant?

[Terry Guo <flameroc@xxxxxxxxx>]

Hi there,

For the below simple case, I think poly1[i] should be hoisted to
outermost loop to avoid loading from innermost loop at each iteration.
But for arm-none-eabi target like cortex-m4, gcc fails to do so. Is
this a normal case or a missing optimization? Please advise.

void
PolyMul (float *poly1, unsigned int n1,
         float *poly2, unsigned int n2,
         float *polymul, unsigned int *nmul)
{
      unsigned int i, j;

         for (i = 0; i <= n1; i++)
   for (j = 0; j <= n2; j++)
      polymul[i+j] += poly1[i] * poly2[j];
}

Thanks.

BR,
Terry