From 47bc554474593652aa2d03b8ef047fbaea9b009a Mon Sep 17 00:00:00 2001 From: David Majnemer Date: Wed, 24 Feb 2016 17:30:48 +0000 Subject: [PATCH] [SimplifyCFG] Use a more elegant solution than r261731 The cleanupret instruction has an invariant that it's 'from' operand be a cleanuppad. This invariant was violated when we removed a dead block which removed a cleanuppad leaving behind a cleanupret with an undef 'from' operand. This was solved in r261731 by staving off the removal of the dead block to a later pass. However, it occured to me that we do not need to do this. Instead, we can simply avoid processing the cleanupret if it has an undef 'from' operand because we know that it will be removed soon. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261754 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Utils/SimplifyCFG.cpp | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index 7a3d368f34c..3e689f6ad9a 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -3521,6 +3521,12 @@ static bool mergeCleanupPad(CleanupReturnInst *RI) { } bool SimplifyCFGOpt::SimplifyCleanupReturn(CleanupReturnInst *RI) { + // It is possible to transiantly have an undef cleanuppad operand because we + // have deleted some, but not all, dead blocks. + // Eventually, this block will be deleted. + if (isa(RI->getOperand(0))) + return false; + if (removeEmptyCleanup(RI)) return true; @@ -5278,17 +5284,9 @@ bool SimplifyCFGOpt::run(BasicBlock *BB) { if ((pred_empty(BB) && BB != &BB->getParent()->getEntryBlock()) || BB->getSinglePredecessor() == BB) { - // Get the block mostly empty. - Changed |= removeAllNonTerminatorAndEHPadInstructions(BB) > 0; - // Now, verify that we succeeded getting the block empty. - // This will not be the case if this unreachable BB creates a token which is - // consumed by other unreachable blocks. - Instruction *FirstNonPHI = BB->getFirstNonPHI(); - if (isa(FirstNonPHI) && FirstNonPHI->use_empty()) { - DEBUG(dbgs() << "Removing BB: \n" << *BB); - DeleteDeadBlock(BB); - return true; - } + DEBUG(dbgs() << "Removing BB: \n" << *BB); + DeleteDeadBlock(BB); + return true; } // Check to see if we can constant propagate this terminator instruction