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Re: Fix PR/46200 -- ivopt bug in test condition cost computation
- From: Zdenek Dvorak <rakdver at kam dot mff dot cuni dot cz>
- To: Xinliang David Li <davidxl at google dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 3 Nov 2010 11:27:57 +0100
- Subject: Re: Fix PR/46200 -- ivopt bug in test condition cost computation
- References: <AANLkTi=TiOqvQsCGUwAP+BdYuNKoXkMR+bUPAJ3LPemail@example.com> <20101030193016.GA20982@kam.mff.cuni.cz> <AANLkTi=Uh+5uLY8TDu393gU4zBQqJN=sq73hCDCnOyDL@mail.gmail.com>
> >> Hi, please review the patch attached. Regression and some performance
> >> test is under going.
> > it would be more consistent to either avoid using aff_combination functions
> > in get_computation_cost_at completely, or rewrite it to use aff_combination
> > instead of the current difference_cost/... functions (however, the latter
> > would probably lead to somewhat slower compilation time). ?The patch should
> > also include a testcase for the problem.
> I agree -- the code for cost computation should match (or probably
> share with) code in the rewrite functions -- however that is a much
> larger task than is needed for this PR.
> I added a test case (marked with x86 target as ivopt are very target
> sensitive). Regression test and minimal perf testing went ok.