Fix PR16110: Handle DBG_VALUE in ConnectedVNInfoEqClasses::Distribute().
Now that the LiveDebugVariables pass is running *after* register
coalescing, the ConnectedVNInfoEqClasses class needs to deal with
DBG_VALUE instructions.
This only comes up when rematerialization during coalescing causes the
remaining live range of a virtual register to separate into two
connected components.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182592 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index dccd847..861e99b 100644
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -909,8 +909,16 @@
MachineOperand &MO = RI.getOperand();
MachineInstr *MI = MO.getParent();
++RI;
- // DBG_VALUE instructions should have been eliminated earlier.
- LiveRangeQuery LRQ(LI, LIS.getInstructionIndex(MI));
+ // DBG_VALUE instructions don't have slot indexes, so get the index of the
+ // instruction before them.
+ // Normally, DBG_VALUE instructions are removed before this function is
+ // called, but it is not a requirement.
+ SlotIndex Idx;
+ if (MI->isDebugValue())
+ Idx = LIS.getSlotIndexes()->getIndexBefore(MI);
+ else
+ Idx = LIS.getInstructionIndex(MI);
+ LiveRangeQuery LRQ(LI, Idx);
const VNInfo *VNI = MO.readsReg() ? LRQ.valueIn() : LRQ.valueDefined();
// In the case of an <undef> use that isn't tied to any def, VNI will be
// NULL. If the use is tied to a def, VNI will be the defined value.