[Fwd: question on optimizing calls to library functions]

[Toon Moene]

Richard Guenther wrote:

> On Wed, Dec 10, 2008 at 5:55 PM, Daniel Franke <franke.daniel@gmail.com> wrote:

>> These questions are probably quite basic, but this is uncharted land for me.
>> There be dragons, I expect.
> 
> ;)

You'd be surprised how simple it is.  I did this about 7-8 years ago for 
g77.  That frontend had a table with various attributes of Fortran 
intrinsics.  It was very easy to add a column to that table saying "this 
function is constant", "this function is pure", or "unknown".

Then, the function that scanned the table for attributes for a certain 
intrinsic would set (the equivalent of) TREE_READONLY on the struct that 
was handed over to the backend based on the added column.

It really was that simple.

-- 
Toon Moene - e-mail: toon@moene.org (*NEW*) - phone: +31 346 214290
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