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| author | Chandler Carruth <chandlerc@gmail.com> | 2011-11-14 09:12:57 +0000 |
|---|---|---|
| committer | Chandler Carruth <chandlerc@gmail.com> | 2011-11-14 09:12:57 +0000 |
| commit | 340d596509129de8c3fa9dbe4184a2b148b78757 (patch) | |
| tree | 5511416c0f2745ec7e3e67bc5af47dfcd3c70dfd /lib/Transforms/Utils/SSAUpdater.cpp | |
| parent | ae5a6fd31575add771264020c8365c6e89d7f912 (diff) | |
Under the hood, MBPI is doing a linear scan of every successor every
time it is queried to compute the probability of a single successor.
This makes computing the probability of every successor of a block in
sequence... really really slow. ;] This switches to a linear walk of the
successors rather than a quadratic one. One of several quadratic
behaviors slowing this pass down.
I'm not really thrilled with moving the sum code into the public
interface of MBPI, but I don't (at the moment) have ideas for a better
interface. My direction I'm thinking in for a better interface is to
have MBPI actually retain much more state and make *all* of these
queries cheap. That's a lot of work, and would require invasive changes.
Until then, this seems like the least bad (ie, least quadratic)
solution. Suggestions welcome.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144530 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Utils/SSAUpdater.cpp')
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