PRE (sometimes) confuses ivopts/scev?

[Daniel Berlin]

On Wed, 26 Jan 2005, Richard Guenther wrote:

> On Wed, 26 Jan 2005, Richard Guenther wrote:
>
>> and the code produced is even better than before with -fno-tree-pre!
>>
>> For a runtime test of the tramp3d testcase we gain about 2% in
>> runtime compared to -fno-tree-pre and about 5% compared to -ftree-pre
>> without your patch.
>
> Btw., we take a compile-time hit of ~0.5% for the tramp3d testcase,
> but this could well be noise.
No, it's probably the loop optimizer init /finalize.
This has *some* overhead, unfortunately, although it's constant.
--Dan