https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101918
Bug ID: 101918
Summary: LTO type mismatches for runtime library functions in
mixed -fdefault-real-8 projects
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: rimvydas.jas at gmail dot com
Target Milestone: ---
$ cat bar.f90
program bar
implicit none
logical :: mask(2,3)
integer :: ai(2,3), vi(5)
real :: ar(2,3), vr(2)
double precision :: ad(2,3), vd(2)
ai = 0
ai(1,1:2) = (/ 1, 2 /)
ar = ai
ad = ai
mask = ai .ne. 0
vi = PACK(ai, ai .gt. 0, vector=(/1,2,3,4,5/))
vd = PACK(ad, mask)
vr = PACK(ar, mask)
call foo()
end program
$ cat foo.f90
subroutine foo
implicit none
real :: ar(2,3), v(1)
ar = 0.
ar(1,1) = 1.
v = PACK(ar, ar > 0.)
end subroutine
$ gfortran -Wall -Wextra -flto -fdefault-real-8 -c foo.f90
$ gfortran -flto -Wall -Wextra foo.o bar.f90
bar.f90:14:19: warning: type of '_gfortran_pack' does not match original
declaration [-Wlto-type-mismatch]
14 | vr = PACK(ar, mask)
| ^
bar.f90:13:19: warning: type of '_gfortran_pack' does not match original
declaration [-Wlto-type-mismatch]
13 | vd = PACK(ad, mask)
| ^
bar.f90:12:46: warning: type of '_gfortran_pack' does not match original
declaration [-Wlto-type-mismatch]
12 | vi = PACK(ai, ai .gt. 0, vector=(/1,2,3,4,5/))
| ^
foo.f90:6:21: note: '_gfortran_pack' was previously declared here
6 | v = PACK(ar, ar > 0.)
| ^
foo.f90:6:21: note: code may be misoptimized unless '-fno-strict-aliasing' is
used
In medium sized mixed C/Fortran codebase there are more instances for:
_gfortran_matmul_r8
_gfortran_pack
_gfortran_reshape_r8
_gfortran_set_convert
_gfortran_shape_4
_gfortran_unpack0
_gfortran_unpack1
Does this mean -flto cannot be used in mixed -fdefault-real-8 and usual modes?
