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path: root/include/llvm/CodeGen/MachineBranchProbabilityInfo.h
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2013-03-20Remove blank line before block comment.Eric Christopher
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177550 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03Sort the #include lines for the include/... tree with the script.Chandler Carruth
AKA: Recompile *ALL* the source code! This one went much better. No manual edits here. I spot-checked for silliness and grep-checked for really broken edits and everything seemed good. It all still compiles. Yell if you see something that looks goofy. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169133 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-27Revert 'Fix a typo 'iff' => 'if''. iff is an abreviation of if and only if. ↵Sylvestre Ledru
See: http://en.wikipedia.org/wiki/If_and_only_if Commit 164767 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164768 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-27Fix a typo 'iff' => 'if'Sylvestre Ledru
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164767 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-20Fix a quadratic algorithm in MachineBranchProbabilityInfo.Jakob Stoklund Olesen
The getSumForBlock function was quadratic in the number of successors because getSuccWeight would perform a linear search for an already known iterator. This patch was originally committed as r161460, but reverted again because of assertion failures. Now that duplicate Machine CFG edges have been eliminated, this works properly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162233 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-08Revert "Fix a quadratic algorithm in MachineBranchProbabilityInfo."Jakob Stoklund Olesen
It caused an assertion failure when compiling consumer-typeset. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161463 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-08Fix a quadratic algorithm in MachineBranchProbabilityInfo.Jakob Stoklund Olesen
The getSumForBlock function was quadratic in the number of successors because getSuccWeight would perform a linear search for an already known iterator. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161460 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-20Add some constantness to BranchProbabilityInfo and BlockFrequnencyInfo.Jakub Staszak
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146986 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-20Unweaken vtables as per ↵David Blaikie
http://llvm.org/docs/CodingStandards.html#ll_virtual_anch git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146960 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-14Under the hood, MBPI is doing a linear scan of every successor everyChandler Carruth
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
2011-11-14Reuse the logic in getEdgeProbability within getHotSucc in order toChandler Carruth
correctly handle blocks whose successor weights sum to more than UINT32_MAX. This is slightly less efficient, but the entire thing is already linear on the number of successors. Calling it within any hot routine is a mistake, and indeed no one is calling it. It also simplifies the code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144527 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-14Fix an overflow bug in MachineBranchProbabilityInfo. This pass relied onChandler Carruth
the sum of the edge weights not overflowing uint32, and crashed when they did. This is generally safe as BranchProbabilityInfo tries to provide this guarantee. However, the CFG can get modified during codegen in a way that grows the *sum* of the edge weights. This doesn't seem unreasonable (imagine just adding more blocks all with the default weight of 16), but it is hard to come up with a case that actually triggers 32-bit overflow. Fortuately, the single-source GCC build is good at this. The solution isn't very pretty, but its no worse than the previous code. We're already summing all of the edge weights on each query, we can sum them, check for an overflow, compute a scale, and sum them again. I've included a *greatly* reduced test case out of the GCC source that triggers it. It's a pretty lame test, as it clearly is just barely triggering the overflow. I'd like to have something that is much more definitive, but I don't understand the fundamental pattern that triggers an explosion in the edge weight sums. The buggy code is duplicated within this file. I'll colapse them into a single implementation in a subsequent commit. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144526 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-14Add a cautionary note to this API. It was not at all obvious to me howChandler Carruth
expensive the most useful interface to this analysis is. Fun story -- it's also not correct. That's getting fixed in another patch. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144523 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-10- Make BranchProbability constructor public.Jakub Staszak
- Add getCompl() method. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134857 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-16Introduce MachineBranchProbabilityInfo class, which has similar API toJakub Staszak
BranchProbabilityInfo (expect setEdgeWeight which is not available here). Branch Weights are kept in MachineBasicBlocks. To turn off this analysis set -use-mbpi=false. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133184 91177308-0d34-0410-b5e6-96231b3b80d8