From 6ba1931d6017eb40a8bf605a7b15d37f18f61bca Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Fri, 18 Sep 2009 08:16:04 +0000 Subject: [PATCH] Fix a bug in sdisel switch lowering code. When it updates the phi nodes in switch successor blocks, it can introduce multiple phi operands of the same value from different blocks (and may not be on the predecessor list). This can be seen on CodeGen/Generic/2006-09-06-SwitchLowering.ll. But it's not known to cause any real regression (but I have added an assertion for it now). llvm-svn: 82214 --- llvm/include/llvm/CodeGen/MachineBasicBlock.h | 7 +++++++ .../CodeGen/SelectionDAG/SelectionDAGISel.cpp | 17 ++++++++++++----- 2 files changed, 19 insertions(+), 5 deletions(-) diff --git a/llvm/include/llvm/CodeGen/MachineBasicBlock.h b/llvm/include/llvm/CodeGen/MachineBasicBlock.h index 2a9e86a04c09..2bfb1babbb1d 100644 --- a/llvm/include/llvm/CodeGen/MachineBasicBlock.h +++ b/llvm/include/llvm/CodeGen/MachineBasicBlock.h @@ -149,6 +149,10 @@ public: return (unsigned)Predecessors.size(); } bool pred_empty() const { return Predecessors.empty(); } + bool isPred(MachineBasicBlock *MBB) const { + return std::find(pred_begin(), pred_end(), MBB) != pred_end(); + } + succ_iterator succ_begin() { return Successors.begin(); } const_succ_iterator succ_begin() const { return Successors.begin(); } succ_iterator succ_end() { return Successors.end(); } @@ -165,6 +169,9 @@ public: return (unsigned)Successors.size(); } bool succ_empty() const { return Successors.empty(); } + bool isSucc(MachineBasicBlock *MBB) const { + return std::find(succ_begin(), succ_end(), MBB) != succ_end(); + } // LiveIn management methods. diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index 19ea64731151..e2fab1b1b800 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -982,6 +982,7 @@ SelectionDAGISel::FinishBasicBlock() { // If we generated any switch lowering information, build and codegen any // additional DAGs necessary. + SmallSet Processed; for (unsigned i = 0, e = SDL->SwitchCases.size(); i != e; ++i) { // Set the current basic block to the mbb we wish to insert the code into BB = SDL->SwitchCases[i].ThisBB; @@ -1004,12 +1005,18 @@ SelectionDAGISel::FinishBasicBlock() { for (unsigned pn = 0; ; ++pn) { assert(pn != SDL->PHINodesToUpdate.size() && "Didn't find PHI entry!"); - if (SDL->PHINodesToUpdate[pn].first == Phi) { - Phi->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pn]. - second, false)); - Phi->addOperand(MachineOperand::CreateMBB(SDL->SwitchCases[i].ThisBB)); + if (SDL->PHINodesToUpdate[pn].first != Phi) + continue; + if (!Processed.insert(pn)) + // Already processed, done. We can't have the value from more than + // one edges. break; - } + Phi->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pn]. + second, false)); + assert(BB->isPred(SDL->SwitchCases[i].ThisBB) && + "phi value cannot come from a bb that is not a predecessor!"); + Phi->addOperand(MachineOperand::CreateMBB(SDL->SwitchCases[i].ThisBB)); + break; } }