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

[tkoenig at gcc dot gnu.org]

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

            Bug ID: 80602
           Summary: Reduce stack usage for blocked matmul
           Product: gcc
           Version: 7.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libfortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tkoenig at gcc dot gnu.org
  Target Milestone: ---

Since the introduction of blocked matmul, we unconditionally
allocate a 65536*sizeof(rtype) buffer on the stack, 0.5 MiB for
double precision.

We should try to reduce this; I have an idea.