Debug info: Don't crash in SelectionDAGISel when a vreg that is being
pointed to by a dbg_value belonging to a function argument is eliminated
during instruction selection.
rdar://problem/15094721.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192011 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index fcde6b5..1d0ed3a 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -408,9 +408,13 @@
EntryMBB->insert(EntryMBB->begin(), MI);
else {
MachineInstr *Def = RegInfo->getVRegDef(Reg);
- MachineBasicBlock::iterator InsertPos = Def;
- // FIXME: VR def may not be in entry block.
- Def->getParent()->insert(llvm::next(InsertPos), MI);
+ if (Def) {
+ MachineBasicBlock::iterator InsertPos = Def;
+ // FIXME: VR def may not be in entry block.
+ Def->getParent()->insert(llvm::next(InsertPos), MI);
+ } else
+ DEBUG(dbgs() << "Dropping debug info for dead vreg"
+ << TargetRegisterInfo::virtReg2Index(Reg) << "\n");
}
// If Reg is live-in then update debug info to track its copy in a vreg.