Technical data

Cray Standard C/C++ Reference Manual
(UNICOS/mk systems) The -h jump option generates jumps instead of
branches to external functions. Branches provide slightly better performance.
However, branches are limited in the distance to which they can transfer control;
jumps have no such limitation. For large programs you may need to use
-h jump with files that generate calls to functions loaded at too great a distance.
2.14.4 -h [no]split (CC, cc)
Default option: -h nosplit
(UNICOS/mk systems) The -h split option instructs the compiler to attempt
to split all loops generated by the compiler into sets of smaller loops. This
technique is intended to increase single processor performance on UNICOS/mk
systems by reducing thrashing of Cray T3E system hardware stream buffers. To
control splitting of loops individually, use the split and nosplit directives.
For more information on these directives and on loop splitting, see Section
3.10.7, page 94.
2.15 Math Options
The following sections describe compiler options with regard to math functions.
2.15.1 -h matherror=method (CC, cc)
Default option: -h matherror=abort
The -h matherror=method option specifies the method of error processing used
if a standard math function encounters an error. The method argument can have
one of the following values:
m
ethod Description
abort If an error is detected, errno is not set. Instead a message is issued
and the program aborts. On systems with IEEE floating-point
hardware, an exception may be raised.
errno If an error is detected, errno is set and the math function
returns to the caller. This method is implied by the -h conform,
-h scalar0, -O0, -Gn, and -g options.
2.15.2 -h [no]fastmd (CC, cc commands)
Default option: -h fastmd
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