[Bug libfortran/80602] Reduce stack usage for blocked matmul

[tkoenig at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80602

--- Comment #2 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
s/t1_dim = (a_dim1-1) * 256 + b_dim1);/t1_dim = (a_dim1-1) * 256 + b_dim1;/