------- Comment #4 from burnus at gcc dot gnu dot org 2007-04-25 19:58 ------- >From the man page: "-malign-double -mno-align-double Control whether GCC aligns "double", "long double", and "long long" variables on a two word boundary or a one word boundary. Aligning "double" variables on a two word boundary will produce code that runs somewhat faster on a Pentium at the expense of more memory. On x86-64, -malign-double is enabled by default."
NOW COMES THE IMPORTANT PART: "Warning: if you use the -malign-double switch, structures containing the above types will be aligned differently than the published application binary interface specifications for the 386 and will not be binary compatible with structures in code compiled without that switch." Thus if you want to use -malign-double, you need to compile at least also the gfortran library with that option. (Maybe other libraries as well.) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31696
