From 9bbe849fc345e5bbb757faafa1d1da8a5a439c42 Mon Sep 17 00:00:00 2001 From: Frits van Bommel Date: Thu, 16 Dec 2010 12:16:00 +0000 Subject: [PATCH] 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. This wasn't a correctness problem, but it broke the fast path for single-predecessor blocks. llvm-svn: 121966 --- llvm/lib/Transforms/Scalar/JumpThreading.cpp | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp index e59ae31e1346..3d218a6585a5 100644 --- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp +++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp @@ -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 // to make a deterministic decision. Pick the first one that appears in the // 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 (i == 0) + if (PredToDestList.empty()) OnlyDest = DestBB; else if (OnlyDest != DestBB) OnlyDest = MultipleDestSentinel;