[PATCH] Fail when PPL 0.11 is not present and CLooG has been requested.

[Tobias Grosser]

On 01/25/2011 11:02 AM, Jakub Jelinek wrote:
> On Tue, Jan 25, 2011 at 10:59:32AM -0500, Tobias Grosser wrote:
>> The intention was to fail if anything else than cloog 0.15 is
>> available and the user did not explicitly state he wants to use
>> another version. The reasoning was that gcc has the policy that two
>> gcc binaries compiled on the same platform for the same set of
>> configure flags should always behave the same. cloog-isl 0.16 and
>> cloog-ppl 0.15 can apply different transformations, so automatically
>> grabbing any of those would be yield to different behavior.
>
> We allow several versions of mpfr/gmp/libmpc, and of course the older
> versions have known bugs (and newer version unknown bugs), thus there are
> some variations in folding for those too.

The original configure patches Andreas proposed actually detected any
cloog version automatically. Those patches where not accepted, but 
Andreas was asked to require an explicit configure switch to change the
accepted version.

I believe this is reasonable, as the different cloog versions not only 
have different bugs, but may differ significantly in the code they 
generate (even though the code calculates the same result in the end).

Tobi