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[Bug fortran/24406] EQUIVALENCE broken in 32-bit code with optimization -O2
- From: "tkoenig at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 6 Feb 2006 20:33:38 -0000
- Subject: [Bug fortran/24406] EQUIVALENCE broken in 32-bit code with optimization -O2
- References: <bug-24406-10567@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #7 from tkoenig at gcc dot gnu dot org 2006-02-06 20:33 -------
Note that http://www.netlib.org/blas/d1mach.f has code
INTEGER SMALL(2)
INTEGER LARGE(2)
INTEGER RIGHT(2)
INTEGER DIVER(2)
INTEGER LOG10(2)
INTEGER SC, CRAY1(38), J
COMMON /D9MACH/ CRAY1
SAVE SMALL, LARGE, RIGHT, DIVER, LOG10, SC
DOUBLE PRECISION DMACH(5)
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))
...
IF (SC .NE. 987) THEN
DMACH(1) = 1.D13
IF ( SMALL(1) .EQ. 1117925532
* .AND. SMALL(2) .EQ. -448790528) THEN
* *** IEEE BIG ENDIAN ***
SMALL(1) = 1048576
SMALL(2) = 0
LARGE(1) = 2146435071
LARGE(2) = -1
RIGHT(1) = 1017118720
RIGHT(2) = 0
DIVER(1) = 1018167296
DIVER(2) = 0
LOG10(1) = 1070810131
LOG10(2) = 1352628735
So, if we don't support this extension, we will potentially break BLAS
(at least the vanilla version distributed with netlib).
--
tkoenig at gcc dot gnu dot org changed:
What |Removed |Added
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CC| |tkoenig at gcc dot gnu dot
| |org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24406