| Submitter | Tobias Burnus |
|---|---|
| Date | May 21, 2012, 5:51 p.m. |
| Message ID | <4FBA809B.40609@net-b.de> |
| Download | mbox | patch |
| Permalink | /patch/160399/ |
| State | New |
| Headers | show |
Comments
Dear Tobias, OK for trunk. As you say, the testcase does no harm and so should be retained. Thanks for the patch. Cheers Paul On 21 May 2012 19:51, Tobias Burnus <burnus@net-b.de> wrote: > First: I have another rather simple patch, which still needs to be reviewed: > http://gcc.gnu.org/ml/fortran/2012-05/msg00086.html > > * * * > > When a realloc on assignment is done, gfortran first obtains the descriptor > by calling realloc_lhs_loop_for_fcn_call and then does the actual function > call using gfc_conv_function_expr. > > However, realloc_lhs_loop_for_fcn_call already causes that the RHS is > evaluated (via gfc_add_loop_ss_code). The double evaluation of an inner > function call, causes memory leaks - and double evaluation > (correctness/performance issue). > > The following code solves the issue. I am not 100% sure that it correctly > does so, but it solved the problem and the testsuite passed. (It might > obsolete the check in "se->direct_byref" of gfc_conv_procedure_call.) > > > The test case is a bit pointless as it will only fail if one uses valgrind > on it; thus, one could consider committing the patch even without. However, > it might not harm to have it in the test suite. > > > Build and regtested on x86-64-linux. > OK for the trunk and 4.6/4.7? > > Tobias
Patch
2012-05-21 Tobias Burnus <burnus@net-b.de> PR fortran/53389 * trans-array.c (gfc_add_loop_ss_code): Don't evaluate expression, if ss->is_alloc_lhs is set. 2012-05-21 Tobias Burnus <burnus@net-b.de> PR fortran/53389 * gfortran.dg/realloc_on_assign_15.f90: New. diff --git a/gcc/fortran/trans-array.c b/gcc/fortran/trans-array.c index b24d1c3..02bb38d 100644 --- a/gcc/fortran/trans-array.c +++ b/gcc/fortran/trans-array.c @@ -2401,6 +2401,11 @@ gfc_add_loop_ss_code (gfc_loopinfo * loop, gfc_ss * ss, bool subscript, bool skip_nested = false; int n; + /* Don't evaluate the arguments for realloc_lhs_loop_for_fcn_call; otherwise, + arguments could get evaluated multiple times. */ + if (ss->is_alloc_lhs) + return; + outer_loop = outermost_loop (loop); /* TODO: This can generate bad code if there are ordering dependencies, --- /dev/null 2012-05-21 07:36:22.011729607 +0200 +++ gcc/gcc/testsuite/gfortran.dg/realloc_on_assign_15.f90 2012-05-21 18:18:59.000000000 +0200 @@ -0,0 +1,40 @@ +! { dg-do run } +! +! PR fortran/53389 +! +! The program was leaking memory before due to +! realloc on assignment and nested functions. +! +module foo + implicit none + contains + + function filler(array, val) + real, dimension(:), intent(in):: array + real, dimension(size(array)):: filler + real, intent(in):: val + + filler=val + + end function filler +end module + +program test + use foo + implicit none + + real, dimension(:), allocatable:: x, y + integer, parameter:: N=1000 !*1000 + integer:: i + +! allocate( x(N) ) + allocate( y(N) ) + y=0.0 + + do i=1, N +! print *,i + x=filler(filler(y, real(2*i)), real(i)) + y=y+x + end do + +end program test