Getting the most out of -qhot
Here are some suggestions for using -qhot:
- Try using -qhot along with -O3 for all of your code. It is designed to have a neutral effect when
no opportunities for transformation exist.
- If the runtime performance of your code can significantly benefit from
automatic inlining and memory locality optimizations, try using -O4 with -qhot=level=0 or -qhot=novector.
- If you encounter unacceptably long compile times (this can
happen with complex loop nests), use -qhot=level=0.
- If your code size is unacceptably large, try using -qcompact along with -qhot.
- If necessary, deactivate -qhot selectively,
allowing it to improve some of your code.