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[Bug fortran/53642] New: Front-end optimization: Wrong string length for deferred-length strings
- From: "burnus at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 12 Jun 2012 08:08:54 +0000
- Subject: [Bug fortran/53642] New: Front-end optimization: Wrong string length for deferred-length strings
- Auto-submitted: auto-generated
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53642
Bug #: 53642
Summary: Front-end optimization: Wrong string length for
deferred-length strings
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: burnus@gcc.gnu.org
CC: damian@rouson.net, tkoenig@gcc.gnu.org
As reported by Damian Rouson at
http://gcc.gnu.org/ml/fortran/2012-06/msg00069.html
Without optimization, the following program prints - and should print:
3 3
However, with -ffrontend-optimize the result is, wrongly,
3 4
Damian: Use -fno-frontend-optimize as work-around.
character(len=4) :: string="123 "
character(:), allocatable :: trimmed
trimmed = trim(string)
print *,len_trim(string),len(trimmed)
end
>From the original dump:
(a) Without FE optimization
_gfortran_string_trim (&len.1, (void * *) &pstr.0, 4, &string);
D.1864 = len.1;
if (trimmed != 0B) goto L.1;
trimmed = (character(kind=1)[1:.trimmed] *)
__builtin_malloc ((sizetype) len.1);
...
.trimmed = len.1;
(b) With FE optimization
if (trimmed != 0B) goto L.1;
trimmed = (character(kind=1)[1:.trimmed] *) __builtin_malloc (4);
...
.trimmed = 4;