Overview Description:
A very simple TEST.F code using D1MACH.F from SLATEC (to initialize machine
constants) compiles correctly using GFORTRAN, but the produced executable gives
nonsense results.
Steps to Reproduce:
1. Save the following program TEST.F and the routine D1MACH.F
**************
program test
implicit none
real(8) d1mach
write(6,*)1,d1mach(1)
write(6,*)2,d1mach(2)
write(6,*)3,d1mach(3)
write(6,*)4,d1mach(4)
write(6,*)5,d1mach(5)
stop
end program test
**************
DOUBLE PRECISION FUNCTION D1MACH (I)
C
INTEGER SMALL(4)
INTEGER LARGE(4)
INTEGER RIGHT(4)
INTEGER DIVER(4)
INTEGER LOG10(4)
C
DOUBLE PRECISION DMACH(5)
SAVE DMACH
EQUIVALENCE (DMACH(1),SMALL(1))
EQUIVALENCE (DMACH(2),LARGE(1))
EQUIVALENCE (DMACH(3),RIGHT(1))
EQUIVALENCE (DMACH(4),DIVER(1))
EQUIVALENCE (DMACH(5),LOG10(1))
C
C MACHINE CONSTANTS FOR THE INTEL i860
C
DATA DMACH(1) / Z'0010000000000000' /
DATA DMACH(2) / Z'7FEFFFFFFFFFFFFF' /
DATA DMACH(3) / Z'3CA0000000000000' /
DATA DMACH(4) / Z'3CB0000000000000' /
DATA DMACH(5) / Z'3FD34413509F79FF' /
C***FIRST EXECUTABLE STATEMENT D1MACH
D1MACH = DMACH(I)
RETURN
C
END
**************
2. Compile with the command
gfortran test.f d1mach.f -o test.exe
3. Run ./test.exe
Actual results:
./test.exe
1 4503599627370496.0
2 9.21886843722740531E+018
3 4.36849163854938112E+018
4 4.37299523817675162E+018
5 4.59909449422310451E+018
Expected results:
./test.exe
1 2.2250738585072014E-308
2 1.7976931348623157E+308
3 1.1102230246251565E-16
4 2.220446049250313E-16
5 0.3010299956639812
Build date and platform:
Dec.05.2007, WinXP (cygwin environment)
Additional information:
1. gfortran --version
GNU Fortran (GCC) 4.3.0 20071017 (experimental) [trunk revision 129419]
2. gcc --version
gcc.exe (GCC) 4.3.0 20071017 (experimental) [trunk revision 129419]
--
Summary: gfortran compiles SLATEC library, but the executable
fails
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: fabio dot subba at polito dot it
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34345
