[llvm] [RemoveDIs][DebugInfo] Handle DPVAssigns in AssignmentTrackingLowering (PR #78980)

[Stephen Tozer via llvm-commits]

================
@@ -1776,33 +1832,73 @@ void AssignmentTrackingLowering::processDbgInstruction(
     return;
 
   if (auto *DAI = dyn_cast<DbgAssignIntrinsic>(&I))
-    processDbgAssign(*DAI, LiveSet);
+    processDbgAssign(DAI, LiveSet);
   else if (auto *DVI = dyn_cast<DbgValueInst>(&I))
-    processDbgValue(*DVI, LiveSet);
+    processDbgValue(DVI, LiveSet);
+}
+void AssignmentTrackingLowering::processDPValue(
+    DPValue &DPV, AssignmentTrackingLowering::BlockInfo *LiveSet) {
+  // Ignore assignments to zero bits of the variable.
+  if (hasZeroSizedFragment(DPV))
+    return;
+
+  if (DPV.isDbgAssign())
+    processDbgAssign(&DPV, LiveSet);
+  else if (DPV.isDbgValue())
+    processDbgValue(&DPV, LiveSet);
 }
 
 void AssignmentTrackingLowering::resetInsertionPoint(Instruction &After) {
   assert(!After.isTerminator() && "Can't insert after a terminator");
-  auto R = InsertBeforeMap.find(After.getNextNode());
+  auto *R = InsertBeforeMap.find(getNextNode(&After));
+  if (R == InsertBeforeMap.end())
+    return;
+  R->second.clear();
+}
+void AssignmentTrackingLowering::resetInsertionPoint(DPValue &After) {
+  auto *R = InsertBeforeMap.find(getNextNode(&After));
----------------
SLTozer wrote:

We can't replace `getNextNode` with `std::next` in this case - the `getNextNode` function here that overloads for DPValue and Instruction doesn't just increment, it has unique behaviour: whichever you call it with, it gets the next `DPValue` _or_ `Instruction`, as-if we were still in the intrinsic format.

https://github.com/llvm/llvm-project/pull/78980