https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117303
Bug ID: 117303
Summary: Link-time optimization optimizes away subroutine
referred to via C_FUNLOC
Product: gcc
Version: 14.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: lto
Assignee: unassigned at gcc dot gnu.org
Reporter: chilikin.k at gmail dot com
Target Milestone: ---
Created attachment 59440
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=59440&action=edit
test.f90
With gfortran 14.2.0, the following program:
$ cat test.f90
MODULE M1
USE, INTRINSIC :: ISO_C_BINDING
TYPE T
TYPE(C_FUNPTR) FUNPTR
END TYPE
TYPE(T), POINTER :: T_POINTER
CONTAINS
SUBROUTINE SET_FUNPTR(F)
TYPE(C_FUNPTR), INTENT(IN) :: F
T_POINTER%FUNPTR = F
END SUBROUTINE
SUBROUTINE S1() BIND(C)
END SUBROUTINE
END MODULE
PROGRAM TEST
USE M1
ALLOCATE(T_POINTER)
CALL SET_FUNPTR(C_FUNLOC(S1))
PRINT *, T_POINTER%FUNPTR
END PROGRAM
works if it is compiled without link-time optimization:
$ gfortran -O1 -o test test.f90
$ ./test
4198811
but with link-time optimization, there is a linker error:
$ gfortran -O1 -flto -o test test.f90
ld: /tmp/ccL2ip3g.ltrans0.ltrans.o: in function `MAIN__':
<artificial>:(.text+0x21): undefined reference to `s1'
collect2: error: ld returned 1 exit status
