https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115711
Bug ID: 115711
Summary: Fortran: extra malloc and copy with transfer
Product: gcc
Version: 14.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: mjr19 at cam dot ac.uk
Target Milestone: ---
subroutine foo(a,b)
complex(kind(1d0))::a
real(kind(1d0))::b(2)
b=transfer(a,b)
end subroutine foo
produces optimal code. But change the declarations to
complex(kind(1d0))::a(2)
real(kind(1d0))::b(4)
and "gfortran-14 -mavx2 -O3" calls malloc, copies a to a temporary location,
then copies into b, and calls free. Generalise to a(n) and b(2*n), passing n as
an extra integer argument, and it calls malloc, memcpy, memcpy, free.
I don't think this double copy is necessary -- just a single copy with no
temporary should suffice.
