On Alpha/Linux, you just follow Installation
Notes to install 64 bit Omni compilers. If you want to use the
Compaq C compiler as default backend, use --with-cc option with "configure" command. like:
When writing this, there is no "known problems" for Omni C
compiler. Not fully tested yet.
Fortran 77 issues:
(including INTEGER*8 on 32 bit environment), INTEGER*8 is only
available when backend C compiler has a integer type that size is 64
bit. Of cource the platforms above clears this.
On Omni Fortran 77 compiler, default size of INTEGER is ALWAYS 4 bytes
even if on 64 bit environment. If need changing it to 8 bytes, specify
"-i8" option for omf77.
When specifying "-i8" option with omf77, all integer
constants will be treat as INTEGER*8 type.
Implied DO in DATA statement will be computed as INTEGER*4 even
if the DO variable (and statr/end/increment value) is
INTEGER*8. Practically, I think no need to treat it as 64 bit. Am I wrong?
Power expressions with INTEGER*8 are currently shrunken to
INTEGER*4. Return value also.
If the process addressing model is 64 bit, pointer variable of
cray pointer extension must be INTEGER*8. And return value of LOC() is
INTEGER*8. So do lock variables for OMP_*_LOCK(), but not tested
yet.
For better perfomance on Linux/Alpha, the Compaq C compiler
is preferred as a backend. It will be several times faster than
gcc. Note that the Compaq C compiler can't handle long input
line. Thus, It might fail to complie fortran souece that have large
initilize block with DATA statement. Will be fixed in next Omni release.