Update DBG_VALUE register operand during LiveInterval operations

Summary:
Handling of DBG_VALUE in ConnectedVNInfoEqClasses::Distribute() was fixed in
PR16110. However DBG_VALUE register operands are not getting updated. This
patch properly resolves the value location.

Reviewers: MatzeB, vsk

Reviewed By: MatzeB

Subscribers: kparzysz, thegameg, vsk, MatzeB, dschuff, sbc100, jgravelle-google, aheejin, sunfish, llvm-commits

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D48994

llvm-svn: 340310

1 files changed, 11 insertions, 11 deletions

diff --git a/llvm/lib/CodeGen/LiveInterval.cpp b/llvm/lib/CodeGen/LiveInterval.cpp
index 83dd982587c..2340b6abd87 100644
--- a/llvm/lib/CodeGen/LiveInterval.cpp
+++ b/llvm/lib/CodeGen/LiveInterval.cpp
@@ -1310,17 +1310,17 @@ void ConnectedVNInfoEqClasses::Distribute(LiveInterval &LI, LiveInterval *LIV[],
     MachineOperand &MO = *RI;
     MachineInstr *MI = RI->getParent();
     ++RI;
-    // 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);
-    LiveQueryResult LRQ = LI.Query(Idx);
-    const VNInfo *VNI = MO.readsReg() ? LRQ.valueIn() : LRQ.valueDefined();
+    const VNInfo *VNI;
+    if (MI->isDebugValue()) {
+      // DBG_VALUE instructions don't have slot indexes, so get the index of
+      // the instruction before them. The value is defined there too.
+      SlotIndex Idx = LIS.getSlotIndexes()->getIndexBefore(*MI);
+      VNI = LI.Query(Idx).valueOut();
+    } else {
+      SlotIndex Idx = LIS.getInstructionIndex(*MI);
+      LiveQueryResult LRQ = LI.Query(Idx);
+      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.
     if (!VNI)