The following program computes the wrong result for a WHERE where different sections of the same array are in both the WHERE and ELSEWHERE section. It's "as if" the ELSEWHERE block were ignored. Dick Hendrickson program RG0023 ! fails on Windows XP ! gcc version 4.4.0 20080312 (experimental) [trunk revision 133139] integer UDA1L(6) integer :: UDA1R(6), expected(6) = (/2,0,5,0,3,0/) LOGICAL LDA(5) UDA1L(1:6) = 0 uda1r = (/1,2,3,4,5,6/) lda = (/ (i/2*2 .ne. I, i=1,5) /) WHERE (LDA) ! expected UDA1L(1:5) = UDA1R(2:6) ! uda1l = 2,0,4,0,6,0 ELSEWHERE UDA1L(2:6) = UDA1R(6:2:-1) !uda1l = 2,0,5,0,3,0 ENDWHERE print *, 'expected = ',expected print *, 'computed = ', uda1l END gfortran:gfortran rg0023.f gfortran:a expected = 2 0 5 0 3 0 computed = 2 0 4 0 6 0
Confirm. The algorithm below does essentially: while (1,0,1,0,1) uda1l( 1 _ 3 _ 5) = 2 3 4 5 6 else udal1 ( _ 3 _ 5 _) = 6 5 4 3 2 done That is 1. uda1l(1) = 2 2. uda1l(3) = 5 <---\__ 3. uda1l(3) = 4 <---/ 4. uda1l(5) = 3 <---\__ 5. uda1l(6) = 4 <---/ The order is wrong. The procedure has to be: 1. Establish control mask (i.e. 1,0,1,0,1) and run WHERE while (1,0,1,0,1) uda1l( 1 _ 3 _ 5) = 2 3 4 5 6 end 2. Establish pending controlmask for ELSEWHERE (i.e. 0,1,0,1,0) elsewhile (0,1,0,1) uda1l( 1 _ 3 _ 5) = 2 3 4 5 6 end { static logical(kind=4) A.2[5] = {1, 0, 1, 0, 1}; static integer(kind=4) A.1[6] = {1, 2, 3, 4, 5, 6}; (void) __builtin_memset ((void *) &uda1l, 0, 24); (void) __builtin_memcpy ((void *) &uda1r, (void *) &A.1, 24); (void) __builtin_memcpy ((void *) &lda, (void *) &A.2, 20); { integer(kind=8) S.3; S.3 = 1; while (1) { if (S.3 > 5) goto L.1; if (lda[S.3 + -1]) { uda1l[S.3 + -1] = uda1r[S.3]; } else { uda1l[S.3] = uda1r[6 - S.3]; } S.3 = S.3 + 1; } L.1:; }
This one should be straightforward, if lengthy to correct: gfc_trans_where_2 is completely correct, as can be verified by doubling up the line making the assignment in the WHERE block. ie: WHERE (LDA) ! expected UDA1L(1:5) = UDA1R(2:6) ! uda1l = 2,0,4,0,6,0 UDA1L(1:5) = UDA1R(2:6) ! uda1l = 2,0,4,0,6,0 ELSEWHERE UDA1L(2:6) = UDA1R(6:2:-1) !uda1l = 2,0,5,0,3,0 ENDWHERE gfc_trans_where_3 is selected for a simple WHERE/ELSEWHERE, with no dependencies and a single assignment expression in each block. This is selected by Dick's testscase. It is also wrong, as indicated by Tobias in #1! gfc_trans_where_3 will have to be split into two loops, instead of a single loop with an expression. Cheers Paul
Subject: Bug 35759 Author: pault Date: Fri May 16 21:12:04 2008 New Revision: 135443 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=135443 Log: 2008-05-16 Paul Thomas <pault@gcc.gnu.org> PR fortran/35756 PR fortran/35759 * trans-stmt.c (gfc_trans_where): Tighten up the dependency check for calling gfc_trans_where_3. PR fortran/35743 * trans-stmt.c (gfc_trans_where_2): Set the mask size to zero if it is calculated to be negative. PR fortran/35745 * trans-stmt.c (gfc_trans_where_3, gfc_trans_where_assign): Set ss->where for scalar right hand sides. * trans-array.c (gfc_add_loop_ss_code): If ss->where is set do not evaluate scalars outside the loop. Clean up whitespace. * trans.h : Add a bitfield 'where' to gfc_ss. 2008-05-16 Paul Thomas <pault@gcc.gnu.org> PR fortran/35756 PR fortran/35759 * gfortran.dg/where_1.f90: New test. PR fortran/35743 PR fortran/35745 * gfortran.dg/where_2.f90: New test. Added: trunk/gcc/testsuite/gfortran.dg/where_1.f90 trunk/gcc/testsuite/gfortran.dg/where_2.f90 Modified: trunk/gcc/fortran/ChangeLog trunk/gcc/fortran/trans-array.c trunk/gcc/fortran/trans-stmt.c trunk/gcc/fortran/trans.h trunk/gcc/testsuite/ChangeLog
Subject: Bug 35759 Author: pault Date: Sat May 17 07:10:13 2008 New Revision: 135461 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=135461 Log: 2008-05-17 Paul Thomas <pault@gcc.gnu.org> Backport from mainline: PR fortran/35756 PR fortran/35759 * trans-stmt.c (gfc_trans_where): Tighten up the dependency check for calling gfc_trans_where_3. PR fortran/35743 * trans-stmt.c (gfc_trans_where_2): Set the mask size to zero if it is calculated to be negative. PR fortran/35745 * trans-stmt.c (gfc_trans_where_3, gfc_trans_where_assign): Set ss->where for scalar right hand sides. * trans-array.c (gfc_add_loop_ss_code): If ss->where is set do not evaluate scalars outside the loop. Clean up whitespace. * trans.h : Add a bitfield 'where' to gfc_ss. PR fortran/36233 * interface.c (compare_actual_formal): Do not check sizes if the actual is BT_PROCEDURE. 2008-05-17 Paul Thomas <pault@gcc.gnu.org> Backport from mainline: PR fortran/35756 PR fortran/35759 * gfortran.dg/where_1.f90: New test. PR fortran/35743 PR fortran/35745 * gfortran.dg/where_2.f90: New test. PR fortran/36233 * gfortran.dg/actual_procedure_1.f90: New test Added: branches/gcc-4_3-branch/gcc/testsuite/gfortran.dg/actual_procedure_1.f90 branches/gcc-4_3-branch/gcc/testsuite/gfortran.dg/where_1.f90 branches/gcc-4_3-branch/gcc/testsuite/gfortran.dg/where_2.f90 Modified: branches/gcc-4_3-branch/gcc/fortran/ChangeLog branches/gcc-4_3-branch/gcc/fortran/interface.c branches/gcc-4_3-branch/gcc/fortran/trans-array.c branches/gcc-4_3-branch/gcc/fortran/trans-stmt.c branches/gcc-4_3-branch/gcc/fortran/trans.h branches/gcc-4_3-branch/gcc/testsuite/ChangeLog
Fixed on trunk and 4.3. Thanks for the report. Paul