From 75abc1ed0618048c3cf6c5b71c9868c10d6c1478 Mon Sep 17 00:00:00 2001 From: Devang Patel Date: Wed, 25 Apr 2007 00:37:04 +0000 Subject: [PATCH] Fix http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20070423/048376.html git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36417 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/CodeGenPrepare.cpp | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp index 8c321f4719b..7a3eac78c56 100644 --- a/lib/Transforms/Scalar/CodeGenPrepare.cpp +++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp @@ -129,6 +129,18 @@ bool CodeGenPrepare::CanMergeBlocks(const BasicBlock *BB, const Instruction *User = cast(*UI); if (User->getParent() != DestBB || !isa(User)) return false; + // If User is inside DestBB block and it is a PHINode then check + // incoming value. If incoming value is not from BB then this is + // a complex condition (e.g. preheaders) we want to avoid here. + if (User->getParent() == DestBB) { + if (const PHINode *UPN = dyn_cast(User)) + for (unsigned I = 0, E = UPN->getNumIncomingValues(); I != E; ++I) { + Instruction *Insn = dyn_cast(UPN->getIncomingValue(I)); + if (Insn && Insn->getParent() == BB && + Insn->getParent() != UPN->getIncomingBlock(I)) + return false; + } + } } } -- 2.34.1