From 9a28cc14a9bc52072649f63308c2a66c9eebe0d1 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Sun, 5 May 2013 18:03:49 +0000 Subject: [PATCH] Teach if-converter to avoid removing BBs whose addresses are takne. rdar://13782395 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181160 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/IfConversion.cpp | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp index eaff93fd7fc..8264d6dbab8 100644 --- a/lib/CodeGen/IfConversion.cpp +++ b/lib/CodeGen/IfConversion.cpp @@ -1039,6 +1039,10 @@ bool IfConverter::IfConvertSimple(BBInfo &BBI, IfcvtKind Kind) { return false; } + if (CvtBBI->BB->hasAddressTaken()) + // Conservatively abort if-conversion if BB's address is taken. + return false; + if (Kind == ICSimpleFalse) if (TII->ReverseBranchCondition(Cond)) llvm_unreachable("Unable to reverse branch condition!"); @@ -1116,6 +1120,10 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) { return false; } + if (CvtBBI->BB->hasAddressTaken()) + // Conservatively abort if-conversion if BB's address is taken. + return false; + if (Kind == ICTriangleFalse || Kind == ICTriangleFRev) if (TII->ReverseBranchCondition(Cond)) llvm_unreachable("Unable to reverse branch condition!"); @@ -1184,7 +1192,8 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) { // block. By not merging them, we make it possible to iteratively // ifcvt the blocks. if (!HasEarlyExit && - NextBBI->BB->pred_size() == 1 && !NextBBI->HasFallThrough) { + NextBBI->BB->pred_size() == 1 && !NextBBI->HasFallThrough && + !NextBBI->BB->hasAddressTaken()) { MergeBlocks(BBI, *NextBBI); FalseBBDead = true; } else { @@ -1234,6 +1243,10 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI, IfcvtKind Kind, return false; } + if (TrueBBI.BB->hasAddressTaken() || FalseBBI.BB->hasAddressTaken()) + // Conservatively abort if-conversion if either BB has its address taken. + return false; + // Put the predicated instructions from the 'true' block before the // instructions from the 'false' block, unless the true block would clobber // the predicate, in which case, do the opposite. @@ -1382,7 +1395,8 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI, IfcvtKind Kind, // tail, add a unconditional branch to it. if (TailBB) { BBInfo &TailBBI = BBAnalysis[TailBB->getNumber()]; - bool CanMergeTail = !TailBBI.HasFallThrough; + bool CanMergeTail = !TailBBI.HasFallThrough && + !TailBBI.BB->hasAddressTaken(); // There may still be a fall-through edge from BBI1 or BBI2 to TailBB; // check if there are any other predecessors besides those. unsigned NumPreds = TailBB->pred_size(); @@ -1551,6 +1565,9 @@ void IfConverter::CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI, /// i.e., when FromBBI's branch is being moved, add those successor edges to /// ToBBI. void IfConverter::MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI, bool AddEdges) { + assert(!FromBBI.BB->hasAddressTaken() && + "Removing a BB whose address is taken!"); + ToBBI.BB->splice(ToBBI.BB->end(), FromBBI.BB, FromBBI.BB->begin(), FromBBI.BB->end());