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Fix a bug in the loop in JumpThreading::ProcessThreadableEdges() where it could falsely produce a MultipleDestSentinel value if the first predecessor ended with an 'indirectbr'. If that happened, it caused an unnecessary FindMostPopularDest() call.

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This wasn't a correctness problem, but it broke the fast path for single-predecessor blocks.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121966 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Frits van Bommel
2010-12-16 12:16:00 +00:00
parent ebef48ea4b
commit 01abcf339f
1 changed files with 2 additions and 2 deletions
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4
lib/Transforms/Scalar/JumpThreading.cpp
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@ -984,7 +984,7 @@ FindMostPopularDest(BasicBlock *BB,
} }
} }
// Okay, now we know the most popular destination. If there is more than // Okay, now we know the most popular destination. If there is more than one
// destination, we need to determine one. This is arbitrary, but we need // destination, we need to determine one. This is arbitrary, but we need
// to make a deterministic decision. Pick the first one that appears in the // to make a deterministic decision. Pick the first one that appears in the
// successor list. // successor list.
@ -1064,7 +1064,7 @@ bool JumpThreading::ProcessThreadableEdges(Value *Cond, BasicBlock *BB,
} }
// If we have exactly one destination, remember it for efficiency below. // If we have exactly one destination, remember it for efficiency below.
if (i == 0) if (PredToDestList.empty())
OnlyDest = DestBB; OnlyDest = DestBB;
else if (OnlyDest != DestBB) else if (OnlyDest != DestBB)
OnlyDest = MultipleDestSentinel; OnlyDest = MultipleDestSentinel;