[Bug fortran/35952] New: Segmentation fault with character strings only when compiling with -funroll-loops and -O3

[Bug fortran/35952] New: Segmentation fault with character strings only when compiling with -funroll-loops and -O3

[john dot young at jrc dot co dot jp]

I attached a short code that produces segmentation faults (or strange cygwin
errors).  The segmentation faults only occur when compiling with both
-funroll-loops and -O3.  If one or the other or neither are used, the program
runs fine.  The code has several examples.  I attached a stackdump for the case
of the three write statements.

System : WinXP, cygwin, gcc version 4.3.0 20080212 (experimental)

==============================
subroutine test_sub(label)

character(len=*),intent(in) :: label

character (len=(len(label)+20)) :: c1
character (len=(len(label)+20)) :: c2
character (len=(len(label)+20)) :: c3

! the below 3 lines cause a segmentation fault
!  print*, len(c1)
!  print*, len(c2)
!  print*, len(c3)

! the below 2 lines produce strange cygwin errors
!          a ### sig_send: wait for sig_complete event failed, signal -34, rc
-1, Win32 error 6
!  print*, len(c1)
!  print*, len(c2)

! the below 1 lines produces no problem
!  print*, len(c3)

! the below 3 lines cause a segmentation fault (I gave the stackdump for this
case)
  write(c1,'(A)') 'a'
  write(c2,'(A)') 'b'
  write(c3,'(A)') 'c'

! the below 2 lines produce strange cygwin erros
!          a ### sig_send: wait for sig_complete event failed, signal -34, rc
-1, Win32 error 6
!  write(c1,'(A)') 'a'
!  write(c2,'(A)') 'b'

! the below 1 lines produces no problem
!  write(c1,'(A)') 'a'

end subroutine test_sub
!======================
program test

  call test_sub('a')
  print*, 'done'

end program test
!======================


-- 
           Summary: Segmentation fault with character strings only when
                    compiling with -funroll-loops and -O3
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: john dot young at jrc dot co dot jp
GCC target triplet: i686-pc-cywgin


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35952

[Bug fortran/35952] Segmentation fault with character strings only when compiling with -funroll-loops and -O3

[john dot young at jrc dot co dot jp]

------- Comment #2 from john dot young at jrc dot co dot jp  2008-04-16 05:34 -------
Created an attachment (id=15483)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15483&action=view)
stackdump for the case of three writes


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35952

[Bug fortran/35952] Segmentation fault with character strings only when compiling with -funroll-loops and -O3

[john dot young at jrc dot co dot jp]

------- Comment #1 from john dot young at jrc dot co dot jp  2008-04-16 05:34 -------
Created an attachment (id=15482)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15482&action=view)
Code that exhibits segmentation fault.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35952

[Bug fortran/35952] Segmentation fault with character strings only when compiling with -funroll-loops and -O3

[tkoenig at gcc dot gnu dot org]

------- Comment #3 from tkoenig at gcc dot gnu dot org  2008-04-16 18:15 -------
I cannot reproduce this on i686-pc-linux-gnu; valgrind
shows no errors.

This may be target specific.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35952

[Bug fortran/35952] Segmentation fault with character strings only when compiling with -funroll-loops and -O3

[jv244 at cam dot ac dot uk]

------- Comment #4 from jv244 at cam dot ac dot uk  2008-08-08 21:43 -------
also works without problems on x86_64 (linux)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35952

[Bug fortran/35952] Segmentation fault with character strings only when compiling with -funroll-loops and -O3

[jvdelisle at gcc dot gnu dot org]

------- Comment #5 from jvdelisle at gcc dot gnu dot org  2008-11-01 12:47 -------
Confirmed.  On trunk R 141238.  I can't get a very usable backtrace on this. 
Maybe valgind will give us a hint on Linux box.  This could also be a
Cygwin.dll issue.


-- 

jvdelisle at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2008-11-01 12:47:05
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35952

[Bug fortran/35952] Segmentation fault with character strings only when compiling with -funroll-loops and -O3

[fxcoudert at gcc dot gnu dot org]

------- Comment #6 from fxcoudert at gcc dot gnu dot org  2009-03-28 13:06 -------
(In reply to comment #5)
> I can't get a very usable backtrace on this. 
> Maybe valgind will give us a hint on Linux box.

With current trunk, valgrind on x86_64-linux reports nothing (tried both -m32
and -m64).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35952

[Bug fortran/35952] Segmentation fault with character strings only when compiling with -funroll-loops and -O3

[jvdelisle at gcc dot gnu dot org]

------- Comment #7 from jvdelisle at gcc dot gnu dot org  2009-10-04 21:25 -------
Assigning to myself only to remind me to investigate to see where this stands
now.


-- 

jvdelisle at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jvdelisle at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2008-11-01 12:47:05         |2009-10-04 21:25:02
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35952

[Bug fortran/35952] Segmentation fault with character strings only when compiling with -funroll-loops and -O3

[jvdelisle at gcc dot gnu dot org]

------- Comment #8 from jvdelisle at gcc dot gnu dot org  2009-10-14 01:09 -------
With gfortran 4.5 trunk r152402 on Cygwin 1.7 the test case executes normally.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35952

[Bug fortran/35952] Segmentation fault with character strings only when compiling with -funroll-loops and -O3

[jvdelisle at gcc dot gnu dot org]

------- Comment #9 from jvdelisle at gcc dot gnu dot org  2009-10-14 01:49 -------
Closing. Works on latest gfortran.  Upgrade to later version.


-- 

jvdelisle at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |WORKSFORME


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35952