From f7a121285003d7f3b970601cffdcccb5bb71fff8 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Wed, 14 Jun 2006 04:46:17 +0000 Subject: [PATCH] Fix Transforms/LoopUnswitch/2006-06-13-SingleEntryPHI.ll, a loop unswitch bug exposed by the recent lcssa work. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28779 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/LoopUnswitch.cpp | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp index 79243a4385b..eb084cbf014 100644 --- a/lib/Transforms/Scalar/LoopUnswitch.cpp +++ b/lib/Transforms/Scalar/LoopUnswitch.cpp @@ -401,7 +401,7 @@ bool LoopUnswitch::UnswitchIfProfitable(Value *LoopCond, Constant *Val,Loop *L){ << Cost << "\n"); return false; } - + // If this is a trivial condition to unswitch (which results in no code // duplication), do it now. Constant *CondVal; @@ -456,6 +456,18 @@ BasicBlock *LoopUnswitch::SplitEdge(BasicBlock *BB, BasicBlock *Succ) { // If the successor only has a single pred, split the top of the successor // block. assert(SP == BB && "CFG broken"); + + // If this block has a single predecessor, remove any phi nodes. Unswitch + // expect that, after split the edges from inside the loop to the exit + // block, that there will be no phi nodes in the new exit block. Single + // entry phi nodes break this assumption. + BasicBlock::iterator I = Succ->begin(); + while (PHINode *PN = dyn_cast(I)) { + PN->replaceAllUsesWith(PN->getIncomingValue(0)); + PN->eraseFromParent(); + I = Succ->begin(); + } + return SplitBlock(Succ, Succ->begin()); } else { // Otherwise, if BB has a single successor, split it at the bottom of the -- 2.34.1