[Bug fortran/106089] false positives with -Wuninitialized for allocation on assignment
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106089 --- Comment #1 from beliavsky at aol dot com --- I see that the report is a duplicate of some reports listed at https://fortran-lang.discourse.group/t/gfortran-uninitialized-warnings/3838/4 56670 – Allocatable-length character var causes bogus warning with -Wuninitialized 1 91442 – Wrong "may be used uninitialized" warning with allocation on assignment 77504 – [10/11/12/13 Regression] "is used uninitialized" with allocatable string and array constructors
[Bug fortran/106089] New: false positives with -Wuninitialized for allocation on assignment
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106089 Bug ID: 106089 Summary: false positives with -Wuninitialized for allocation on assignment Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: beliavsky at aol dot com Target Milestone: --- For the code implicit none integer, allocatable :: v(:) character(len=1), allocatable :: a(:) a = ["a"] print*, a v = [10,20] print*,v end gfortran -Wall -Wextra xgfortran_warn.f90 gives many incorrect warnings: xgfortran_warn.f90:4:9: 4 | a = ["a"] | ^ Warning: 'a.offset' is used uninitialized [-Wuninitialized] xgfortran_warn.f90:3:37: 3 | character(len=1), allocatable :: a(:) | ^ note: 'a' declared here xgfortran_warn.f90:4:9: 4 | a = ["a"] | ^ Warning: 'a.dim[0].lbound' is used uninitialized [-Wuninitialized] xgfortran_warn.f90:3:37: 3 | character(len=1), allocatable :: a(:) | ^ note: 'a' declared here xgfortran_warn.f90:4:9: 4 | a = ["a"] | ^ Warning: 'a.dim[0].ubound' is used uninitialized [-Wuninitialized] xgfortran_warn.f90:3:37: 3 | character(len=1), allocatable :: a(:) | ^ note: 'a' declared here xgfortran_warn.f90:4:9: 4 | a = ["a"] | ^ Warning: 'a.dim[0].lbound' may be used uninitialized [-Wmaybe-uninitialized] xgfortran_warn.f90:3:37: 3 | character(len=1), allocatable :: a(:) | ^ note: 'a' declared here xgfortran_warn.f90:4:9: 4 | a = ["a"] | ^ Warning: 'a.dim[0].ubound' may be used uninitialized [-Wmaybe-uninitialized] xgfortran_warn.f90:3:37: 3 | character(len=1), allocatable :: a(:) | ^ note: 'a' declared here xgfortran_warn.f90:4:9: 4 | a = ["a"] | ^ Warning: 'a.dim[0].ubound' may be used uninitialized [-Wmaybe-uninitialized] xgfortran_warn.f90:3:37: 3 | character(len=1), allocatable :: a(:) | ^ note: 'a' declared here xgfortran_warn.f90:4:9: 4 | a = ["a"] | ^ Warning: 'a.dim[0].lbound' may be used uninitialized [-Wmaybe-uninitialized] xgfortran_warn.f90:3:37: 3 | character(len=1), allocatable :: a(:) | ^ note: 'a' declared here The output is the same for gfortran 12.0.1 20220213 on Windows from equation.com and gfortran-11 on WSL2. The code combines two codes from a Fortran Discourse discussion https://fortran-lang.discourse.group/t/gfortran-uninitialized-warnings/3838 .
[Bug fortran/31921] New: crash for FUNCTION with RESULT specifier
module mman
implicit none
private
public mskew,nskew
contains
function nskew() result(y)
real :: y(1)
call skewm(y)
end function nskew
!
function mskew()
real :: mskew(1)
call skewm(mskew)
end function mskew
!
subroutine skewm(smat)
real, intent(out) :: smat(1)
smat = 0.0
end subroutine skewm
end module mman
!
program mtst
use mman, only: mskew,nskew
implicit none
print*,"(1) calling nskew"
print*,nskew()
print*,"(2) calling mskew"
print*,mskew()
print*,"(3) done"
end program mtst
Compiling with mingw gfortran 20070506 with the default options gives the
incorrect warning message
xfunc_bug.f90: In function 'mskew':
xfunc_bug.f90:13: warning: Function does not return a value
and at run time the output is
(1) calling nskew
0.00
(2) calling mskew
--
Summary: crash for FUNCTION with RESULT specifier
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: beliavsky at aol dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31921
[Bug fortran/31867] function result with character LEN computed at run time
--- Comment #4 from beliavsky at aol dot com 2007-05-09 15:27 --- (In reply to comment #2) > I get: > words = 'two three' > On x86-64-gnu/linux with latest 4.3 > I wonder if this is one that we recently fixed. Can you try with a more > recent > build? Using Mingw 20070506, the problem persists. The behavior of the compiled program is erratic. Running the compiled program in one Windows console (command line) I get different "garbage" characters appended to the correct output than when running it in a different Windows console. Running the program repeatedly in the same console gives the same results. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31867
[Bug fortran/31867] New: function result with character LEN computed at run time
The program
module util_mod
implicit none
contains
function join(words,sep) result(str)
! trim and concatenate a vector of character variables,
! inserting sep between them
character (len=*), intent(in):: words(:),sep
character (len=(size(words)-1)*len(sep) + sum(len_trim(words))) :: str
integer :: i,nw
nw = size(words)
str = ""
if (nw < 1) then
return
else
str = words(1)
end if
do i=2,nw
str = trim(str) // sep // words(i)
end do
end function join
end module util_mod
!
program xjoin
use util_mod, only: join
implicit none
character (len=5) :: words(2) = (/"two ","three"/)
write (*,"(1x,'words = ',a)") "'"//join(words," ")//"'"
end program xjoin
gives
words = 'two threeg9'
but I think it should give
words = 'two three'
gfortran -v says
Using built-in specs.
Target: i386-pc-mingw32
Configured with: ../trunk/configure --prefix=/mingw
--enable-languages=c,fortran,c++,objc,obj-c++ --with-gmp=/home/coudert/local
--disable-nls --with-ld=/mingw/bin/ld --with-as=/mingw/bin/as --disable-werror
--enable-bootstrap --enable-threads --build=i386-pc-mingw32 --disable-shared
--enable-libgomp
Thread model: win32
gcc version 4.3.0 20070406 (experimental)
--
Summary: function result with character LEN computed at run time
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: beliavsky at aol dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31867
[Bug fortran/31672] New: Not Implemented: Initialization of overlapping variables
This feature is used "classic" Fortran 77 libraries such as Starpac, as
mentioned in comp.lang.fortran on 23-Apr-2007 .
c:\fortran> type d1mach.f90
function d1mach(i)
implicit none
double precision d1mach,dmach(5)
integer i,large(4),small(4)
equivalence ( dmach(1), small(1) )
equivalence ( dmach(2), large(1) )
data small(1),small(2) / 0, 1048576/
data large(1),large(2) /-1,2146435071/
d1mach = 0.0d0
end function d1mach
c:\fortran> gfortran -c -v d1mach.f90
Using built-in specs.
Target: i386-pc-mingw32
Configured with: ../trunk/configure --prefix=/mingw
--enable-languages=c,fortran,c++,objc,obj-c++ --with-gmp=/home/coudert/local
--disable-nls --with-ld=/mingw/bin/ld --with-as=/mingw/bin/as --disable-werror
--enable-bootstrap --enable-threads --build=i386-pc-mingw32 --disable-shared
--enable-libgomp
Thread model: win32
gcc version 4.3.0 20070406 (experimental)
c:/programs/gfortran/bin/../libexec/gcc/i386-pc-mingw32/4.3.0/f951.exe
d1mach.f90 -quiet -dumpbase d1mach.f90 -mtune=i386 -auxbase d1mach -version
-fintrinsic-modules-path
c:/programs/gfortran/bin/../lib/gcc/i386-pc-mingw32/4.3.0/finclude -o
C:\DOCUME~1\vrao\LOCALS~1\Temp/cchM3Bia.s
GNU F95 version 4.3.0 20070406 (experimental) (i386-pc-mingw32)
compiled by GNU C version 4.3.0 20070406 (experimental).
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
d1mach.f90: In function 'd1mach':
d1mach.f90:1: fatal error: gfc_todo: Not Implemented: Initialization of
overlapping variables
compilation terminated.
--
Summary: Not Implemented: Initialization of overlapping variables
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: beliavsky at aol dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31672
