[mpich-discuss] Duplicated include paths and optimization

[Dave Goodell]

On Apr 26, 2011, at 12:58 PM CDT, Yauheni Zelenko wrote:

> I looked into verbose output of MPICH2 compilation (for MVAPICH2 build debugging) and I found many duplicated include paths like:
[...]
> I'm not sure it's easy to fix, but verbose output will be much more readable after removing duplicates.

It's not especially easy to fix right now, or at least not in a way that we can guarantee is safe against more exotic quoting.  We know about the problem, we also dislike it, but it's just a bit too much effort to fix something that is primarily an aesthetics issue.

> Additionally optimization level looks dependent on both --enable-strict and --enable-fast. Probably will be good idea to control optimization level in one place.

Another known issue.  It's user-unfriendly, but most compilers (esp. GCC) won't actually be very strict unless optimization levels >= O2 are selected because those higher optimization levels contain the necessary passes for certain kinds of error checking.  "--enable-strict" is primarily intended to be a developer-used option that helps keep us honest when developing the code on platforms that are either very permissive or otherwise non-buggy.  For example, it helps us keep GCC-specific syntax extensions out of the codebase, which means that MPICH2 is more likely to work with stricter/older/buggier compilers that a user might use.

-Dave