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Re: PRE (sometimes) confuses ivopts/scev?




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


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