The following code is miscompiled at -O3 with trunk and 4.5.0:
! From forall_12.f90
! Fails with loop reversal at -O3
!
character(len=1) :: b(4) = (/"1","2","3","4"/), c(4)
c = b
i = 1
! This statement must be here for the abort below
b(1:3)(i:i) = b(2:4)(i:i)
b = c
b(4:2:-1)(i:i) = b(3:1:-1)(i:i)
! This fails. If the condition is printed, the result is F F F F
if (any (b .ne. (/"1","1","2","3"/))) i = 2
print *, b
print *, b .ne. (/"1","1","2","3"/)
if (i == 2) call abort
end
[macbook] f90/bug% gfc -O3 forall_12_db.f90
[macbook] f90/bug% a.out
1123
F F F F
Abort
Abort is not called if the test 'if (any ...' is replaced with
if (any (b .ne. (/"1","1","2","4"/))) i = 2
As spotted by Tobias Burnus, the problem comes from
...
static character(kind=1)[1:1] * A.5[4] = {&"1"[1]{lb: 1 sz: 1}, &"1"[1]{lb: 1
sz: 1}, &"2"[1]{lb: 1 sz: 1}, &"3"[1]{lb: 1 sz: 1}};
...
<bb 5>:
D.1645_85 = A.5[3];
D.1646_86 = (*D.1645_85)[1]{lb: 1 sz: 1};
if (D.1646_86 != D.1596_154)
goto <bb 7>;
else
goto <bb 6>;
<bb 6>:
...
--
Summary: [4.5/4.6 Regression] wrong code at -O3
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: dominiq at lps dot ens dot fr
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44592
