gfortran(gcc-4.0.0) silently changes the value of variables in equivalence statements. The following code prints the value "0" and not "1": implicit none integer O DIMENSION O(300000) COMMON /IBM/O integer b,e,r,s,v,u,w,x,c EQUIVALENCE(O(1),B),(O(2),E),(O(3),R),(O(4),S),(O(5),V),(O(6),U), *(O(7),W),(O(8),X),(C,O(12)) O(9)=1 CALL MYSUB END subroutine MYSUB implicit none integer O DIMENSION O(300000) COMMON /IBM/O integer b,e,r,s,v,u,w,x,c EQUIVALENCE(O(1),B),(O(2),E),(O(3),R),(O(4),S),(O(5),V),(O(6),U), *(O(7),W),(O(8),X),(C,O(12)) WRITE(6,*) "IN MYSUB: O(9)= ", O(9) RETURN END As always, thank you. You folks do excellent work. Sincerely, Mike Albert
Created attachment 9212 [details] minimal test case The bug persists in gcc version 4.1.0 20050702 (experimental) If I replace: EQUIVALENCE(K(1),I),(J,K(2)) with EQUIVALENCE(I,K(1)),(J,K(2)) or EQUIVALENCE(K(1),I),(K(2),J) the code does not demonstrate this problem. Thank you.
In this case, we forget the common block name. From the .t02.original: MAIN__ () { static union { int4 o[300000]; } equiv.0; equiv.0.o[8] = 1; mysub (); } mysub () { static union { int4 o[300000]; } equiv.1; The strange thing is that this goes away when the last equivalence is deleted: MAIN__ () { ibm.o[8] = 1; mysub (); mysub () { ... What I find also very strange is the missing closing brace in MAIN__. This may point towards memory corruption somewhere. $ gfortran -v Using built-in specs. Target: ia64-unknown-linux-gnu Configured with: ../gcc-4.1-20050702/configure --prefix=/home/zfkts --enable- languages=c,f95 Thread model: posix gcc version 4.1.0 20050702 (experimental)
(In reply to comment #2) First, thank you for taking an interest in this issue. Secondly, if I may speculate, it seems to me that there is a problem in how gfc_equiv structures are marked as "used" in trans-common.c As an expriment, if in gfc_trans_common I commented-out finish_equivalences, then the example "bug.f" (see attachment above) produces the expected output. This is clearly not a solution, but might be a hint at the problem. Thank you.
(In reply to comment #3) One more bit of speculation. I still think there is an issue with marking "->used" in gfc_equiv structures. The following change will make the test case "work", but since I only vaguely understand the intention of the code, I wouldn't recommoned its use: *** trans-common.c 2005-07-06 13:17:28.029531913 -0400 --- trans-common.c.orig 2005-07-05 21:09:38.882901773 -0400 *************** *** 695,701 **** { add_condition (n, eq, other); eq->used = 1; - other->used = 1; /*FIXME or HELPME, this is mostly a guess*/ found = TRUE; /* If this symbol is the first in the chain we may find other matches. Otherwise we can skip to the next equivalence. */ --- 695,700 ----
Mike, As I promised on the fortran list, I am about to tackle module equivalences. Since there are clearly associated issues with equivalences in general, I need to come to grips with those too. Your contributions to the investigation are very welcome and most helpful. Did you go any further with this? Paul Thomas
Subject: Re: gfortran silently changes values in equilvane nce'd variables Greetings! On Wed, 3 Aug 2005, paulthomas2 at wanadoo dot fr wrote: > ------- Additional Comments From paulthomas2 at wanadoo dot fr > 2005-08-03 07:06 ------- > Mike, > > As I promised on the fortran list, I am about to tackle module > equivalences. I really appreciate the work folks like you do. > Your contributions to the investigation are very welcome and most > helpful. Did > you go any further with this? Thank you, but no, I got as far as the messages which I posted, then decided that I really didn't know what I was doing and stopped. I should explain that my immediate purpose was a program called "EGSnrc" and there seem to be other issues with regards to compiling this under gfortran, so I've gone back to g77. I am a little busy, but I might be able to try some more. However, I have no real experience programming compilers, and I don't think I understand the intended logic of the algorithms in the code which I tweaked. Is there something I should have read that would give me a clue? Again, thanks. Sincerely, Mike Albert
> I am a little busy, but I might be able to try some more. > However, I have no real experience programming compilers, > and I don't think I understand the Join the club! > intended logic of the algorithms in the code which > I tweaked. Is there something I should have read > that would give me a clue? Unfortunately, no. I think that it is gong to take me a week or two to come to grips with how this should work. There are many other problems with modules/equivalences/common, which need to be sorted out together. Thank you again for your help. Paul T
This is amusing..... integer o(4), b, c COMMON /IBM/ o EQUIVALENCE (o(1),b),(C,o(4)) o(3)=1 CALL MYSUB1 CALL MYSUB2 END subroutine MYSUB1 integer o (4), b, c COMMON /IBM/ o EQUIVALENCE (o(1), b), (o(4), c) WRITE (6,*) "IN MYSUB1: o(3)= ", o(3) RETURN END subroutine MYSUB2 integer o (4), b, c COMMON /IBM/ o EQUIVALENCE (o(1), b), (c, o(4)) WRITE (6,*) "IN MYSUB2: o(3)= ", o(3) RETURN END IN MYSUB1: o(3)= 0 IN MYSUB2: o(3)= 134519416 The code shows that SUB1 references the common block, whereas SUB2 goes for a home grown equivalence. This is a good clue as to where things are failing.
Subject: Bug 22304 CVSROOT: /cvs/gcc Module name: gcc Changes by: pault@gcc.gnu.org 2005-09-09 00:23:18 Modified files: gcc/fortran : gfortran.h match.c module.c primary.c trans-common.c trans-decl.c ChangeLog gcc/testsuite : ChangeLog Added files: gcc/testsuite/gfortran.dg: module_blank_common.f90 module_double_reuse.f90 common_equivalence_1.f common_equivalence_2.f common_equivalence_3.f contained_equivalence_1.f90 module_commons_1.f90 module_equivalence_1.f90 nested_modules_1.f90 Log message: 2005-09-09 Paul Thomas <pault@gcc.gnu.org> PR fortran/18878 * module.c (find_use_name_n): Based on original find_use_name. Either counts number of use names for a given real name or returns use name n. (find_use_name, number_use_names): Interfaces to the function find_use_name_n. (read_module): Add the logic and calls to these functions, so that mutiple reuses of the same real name are loaded. 2005-09-09 Paul Thomas <pault@gcc.gnu.org> PR fortran/22304 PR fortran/23270 PR fortran/18870 PR fortran/16511 PR fortran/17917 * gfortran.h: Move definition of BLANK_COMMON_NAME from trans- common.c so that it is accessible to module.c. Add common_head field to gfc_symbol structure. Add field for the equivalence name AND new attr field, in_equivalence. * match.c (gfc_match_common, gfc_match_equivalence): In loops that flag common block equivalences, emit an error if the common blocks are different, using sym->common_head as the common block identifier. Ensure that symbols that are equivalence associated with a common block are marked as being in_common. * module.c (write_blank_common): New. (write_common): Use unmangled common block name. (load_equiv): New function ported from g95. (read_module): Call load_equiv. (write_equiv): New function ported from g95. Correct string referencing for gfc functions. Give module equivalences a unique name. (write_module): Call write_equiv and write_blank_common. * primary.c (match_variable) Old gfc_match_variable, made static and third argument provided to indicate if parent namespace to be visited or not. (gfc_match_variable) New. Interface to match_variable. (gfc_match_equiv_variable) New. Interface to match_variable. * trans-common.c (finish_equivalences): Provide the call to create_common with a gfc_common_header so that module equivalences are made external, rather than local. (find_equivalences): Ensure that all members in common block equivalences are marked as used. This prevents the subsequent call to this function from making local unions. * trans-decl.c (gfc_generate_function_code): Move the call to gfc_generate_contained_functions to after the call to gfc_trans_common so the use-associated, contained common blocks produce the correct references. (gfc_create_module_variable): Return for equivalenced symbols with existing backend declaration. 2005-09-09 Paul Thomas <pault@gcc.gnu.org> PR fortran/18878 * gfortran.dg/module_double_reuse.f90: New. 2005-09-09 Paul Thomas <pault@gcc.gnu.org> PR fortran/23270 PR fortran/22304 PR fortran/18870 PR fortran/17917 PR fortran/16511 * gfortran.dg/common_equivalence_1.f: New. * gfortran.dg/common_equivalence_2.f: New. * gfortran.dg/common_equivalence_3.f: New. * gfortran.dg/contained_equivalence_1.f90: New. * gfortran.dg/module_blank_common.f90: New. * gfortran.dg/module_commons_1.f90: New. * gfortran.dg/module_equivalence_1.f90: New. * gfortran.dg/nested_modules_1.f90: New. * gfortran.dg/g77/19990905-0.f: Remove XFAIL, rearrange equivalences and add comment to connect the test with the PR. Patches: http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/gfortran.h.diff?cvsroot=gcc&r1=1.84&r2=1.85 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/match.c.diff?cvsroot=gcc&r1=1.44&r2=1.45 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/module.c.diff?cvsroot=gcc&r1=1.35&r2=1.36 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/primary.c.diff?cvsroot=gcc&r1=1.35&r2=1.36 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/trans-common.c.diff?cvsroot=gcc&r1=1.30&r2=1.31 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/trans-decl.c.diff?cvsroot=gcc&r1=1.67&r2=1.68 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/ChangeLog.diff?cvsroot=gcc&r1=1.543&r2=1.544 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/module_blank_common.f90.diff?cvsroot=gcc&r1=NONE&r2=1.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/module_double_reuse.f90.diff?cvsroot=gcc&r1=NONE&r2=1.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/common_equivalence_1.f.diff?cvsroot=gcc&r1=NONE&r2=1.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/common_equivalence_2.f.diff?cvsroot=gcc&r1=NONE&r2=1.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/common_equivalence_3.f.diff?cvsroot=gcc&r1=NONE&r2=1.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/contained_equivalence_1.f90.diff?cvsroot=gcc&r1=NONE&r2=1.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/module_commons_1.f90.diff?cvsroot=gcc&r1=NONE&r2=1.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/module_equivalence_1.f90.diff?cvsroot=gcc&r1=NONE&r2=1.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/nested_modules_1.f90.diff?cvsroot=gcc&r1=NONE&r2=1.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.6033&r2=1.6034
Subject: Bug 22304 CVSROOT: /cvs/gcc Module name: gcc Branch: gcc-4_0-branch Changes by: pault@gcc.gnu.org 2005-09-09 09:06:09 Modified files: gcc/fortran : gfortran.h match.h match.c module.c primary.c trans-common.c trans-decl.c ChangeLog gcc/testsuite/gfortran.dg/g77: 19990905-0.f gcc/testsuite : ChangeLog Added files: gcc/testsuite/gfortran.dg: module_blank_common.f90 module_double_reuse.f90 common_equivalence_1.f common_equivalence_2.f common_equivalence_3.f contained_equivalence_1.f90 module_commons_1.f90 module_equivalence_1.f90 nested_modules_1.f90 Log message: 2005-09-09 Paul Thomas <pault@gcc.gnu.org> PR fortran/18878 * module.c (find_use_name_n): Based on original find_use_name. Either counts number of use names for a given real name or returns use name n. (find_use_name, number_use_names): Interfaces to the function find_use_name_n. (read_module): Add the logic and calls to these functions, so that mutiple reuses of the same real name are loaded. 2005-09-09 Paul Thomas <pault@gcc.gnu.org> PR fortran/22304 PR fortran/23270 PR fortran/18870 PR fortran/16511 PR fortran/17917 * gfortran.h: Move definition of BLANK_COMMON_NAME from trans- common.c so that it is accessible to module.c. Add common_head field to gfc_symbol structure. Add field for the equivalence name AND new attr field, in_equivalence. * match.c (gfc_match_common, gfc_match_equivalence): In loops that flag common block equivalences, emit an error if the common blocks are different, using sym->common_head as the common block identifier. Ensure that symbols that are equivalence associated with a common block are marked as being in_common. * module.c (write_blank_common): New. (write_common): Use unmangled common block name. (load_equiv): New function ported from g95. (read_module): Call load_equiv. (write_equiv): New function ported from g95. Correct string referencing for gfc functions. Give module equivalences a unique name. (write_module): Call write_equiv and write_blank_common. * primary.c (match_variable) Old gfc_match_variable, made static and third argument provided to indicate if parent namespace to be visited or not. (gfc_match_variable): New. Interface to match_variable. (gfc_match_equiv_variable): New. Interface to match_variable. * trans-common.c (finish_equivalences): Provide the call to create_common with a gfc_common_header so that module equivalences are made external, rather than local. (find_equivalences): Ensure that all members in common block equivalences are marked as used. This prevents the subsequent call to this function from making local unions. * trans-decl.c (gfc_generate_function_code): Move the call to gfc_generate_contained_functions to after the call to gfc_trans_common so the use-associated, contained common blocks produce the correct references. (gfc_create_module_variable): Return for equivalenced symbols with existing backend declaration. 2005-09-09 Paul Thomas <pault@gcc.gnu.org> PR fortran/18878 * gfortran.dg/module_double_reuse.f90: New. 2005-09-09 Paul Thomas <pault@gcc.gnu.org> PR fortran/23270 PR fortran/22304 PR fortran/18870 PR fortran/17917 PR fortran/16511 * gfortran.dg/common_equivalence_1.f: New. * gfortran.dg/common_equivalence_2.f: New. * gfortran.dg/common_equivalence_3.f: New. * gfortran.dg/contained_equivalence_1.f90: New. * gfortran.dg/module_blank_common.f90: New. * gfortran.dg/module_commons_1.f90: New. * gfortran.dg/module_equivalence_1.f90: New. * gfortran.dg/nested_modules_1.f90: New. * gfortran.dg/g77/19990905-0.f: Remove XFAIL, rearrange equivalences and add comment to connect the test with the PR. Patches: http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/gfortran.h.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.58.2.16&r2=1.58.2.17 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/match.h.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.10.36.1&r2=1.10.36.2 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/match.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.31.8.11&r2=1.31.8.12 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/module.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.31.2.2&r2=1.31.2.3 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/primary.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.22.2.10&r2=1.22.2.11 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/trans-common.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.23.2.4&r2=1.23.2.5 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/trans-decl.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.54.2.5&r2=1.54.2.6 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.335.2.114&r2=1.335.2.115 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/module_blank_common.f90.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/module_double_reuse.f90.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/common_equivalence_1.f.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/common_equivalence_2.f.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/common_equivalence_3.f.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/contained_equivalence_1.f90.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/module_commons_1.f90.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/module_equivalence_1.f90.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/nested_modules_1.f90.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/g77/19990905-0.f.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.1&r2=1.1.48.1 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.5084.2.394&r2=1.5084.2.395
Fixed.