Re: [AMBER-Developers] SSE2 / SSE3 settings no longer used for ifort?

From: Ben Roberts <>
Date: Mon, 26 Oct 2009 14:12:36 -0400


> Ok, i switched it to -axSTPW.
> For future work:
>> However, the warning here is that compilers older than 10.0 do not support
>> the S option I believe. Additionally not all the sub options are supported
>> by all compiler versions. Then to make things more complicated in ifort 11.0
>> and 11.1 Intel has set the -axS... options to deprecated and now says you
>> need to use the more verbose SSE4.2,SSE4.1 options etc. I assume that come
>> ifort v12 they will remove the -axS... options entirely and hence things
>> will no longer build. Of course SSE4.2 etc does not work with pre 11.0
>> compilers and thus the -fast option has its appeal except for the fact that
>> it introduces additional issues. So maybe for now we should use -axWPS which
>> should work with most post 10.0 Intel compilers for the time being - maybe
>> including the T option as well. Then we can issue a patch if Intel breaks
>> this in 12.0.
>>> There is also the compiler version wrinkle as you mentioned.
>>> If someone has specific recommendations on options then make them;
>>> otherwise, i suggest we make the small -axS -> -axWPS change for
>>> the ambertools release and then try fast which will give us months
>>> to test drive it b4 amber11.
>> The only other thing is to try to detect the compiler version but this may
>> get horribly complicated. Asking the user to provide the compiler version to
>> configure is probably a recipe for disaster so if we do have specifics for
>> specific compiler versions it should probably be selected automatically.

Intel 11 on the Mac doesn't like -axW, at least. So we're already into
compiler version Hades.

I'm trying to tweak my configure script to best suit Intel 11/Snow
Leopard. But I'm loath to upload my changes, because I fear they won't
be backwards-compatible. (I already managed to break the configure
script once that way.) Is it worth trying to detect compiler versions
automatically, or is that just opening up a can of worms?


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Received on Mon Oct 26 2009 - 11:30:05 PDT
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