From 6ba1931d6017eb40a8bf605a7b15d37f18f61bca Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Fri, 18 Sep 2009 08:16:04 +0000 Subject: 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/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) (limited to 'llvm/lib/CodeGen') diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index 19ea6473115..e2fab1b1b80 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; } } -- cgit v1.2.3