[Rd] -malign-double

Paul Gilbert gilb@home.com
Wed, 28 Feb 2001 10:43:19 -0500

I was just looking at the documentation for g77 and noticed the
following, and also noticed that it is not used when fortran for a
package is compiled with the default (i.e. no Makefile in src
directory.)  Should it be considered?

Paul Gilbert
     (Intel x86 architecture only.)

     Noticeably improves performance of `g77' programs making heavy use
     of `REAL(KIND=2)' (`DOUBLE PRECISION') data on some systems.  In
     particular, systems using Pentium, Pentium Pro, 586, and 686
     implementations of the i386 architecture execute programs faster
     when `REAL(KIND=2)' (`DOUBLE PRECISION') data are aligned on
     64-bit boundaries in memory.

     This option can, at least, make benchmark results more consistent
     across various system configurations, versions of the program, and
     data sets.

     *Note:* The warning in the `gcc' documentation about this option
     does not apply, generally speaking, to Fortran code compiled by

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