[llvm] [VPlan] Track VPValue names in VPlan. (PR #81411)

[via llvm-commits]

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@@ -1373,32 +1362,73 @@ VPInterleavedAccessInfo::VPInterleavedAccessInfo(VPlan &Plan,
   visitRegion(Plan.getVectorLoopRegion(), Old2New, IAI);
 }
 
-void VPSlotTracker::assignSlot(const VPValue *V) {
-  if (V->getUnderlyingValue())
+void VPSlotTracker::assignSlotOrName(const VPValue *V) {
+  if (auto *UV = V->getUnderlyingValue()) {
+    std::string Name;
+    raw_string_ostream S(Name);
+    UV->printAsOperand(S, false);
+    deduplicateName(V, Name);
     return;
+  }
   assert(!Slots.contains(V) && "VPValue already has a slot!");
   Slots[V] = NextSlot++;
 }
 
-void VPSlotTracker::assignSlots(const VPlan &Plan) {
+void VPSlotTracker::assignSlotsOrNames(const VPlan &Plan) {
   if (Plan.VFxUF.getNumUsers() > 0)
-    assignSlot(&Plan.VFxUF);
-  assignSlot(&Plan.VectorTripCount);
+    assignSlotOrName(&Plan.VFxUF);
+  assignSlotOrName(&Plan.VectorTripCount);
   if (Plan.BackedgeTakenCount)
-    assignSlot(Plan.BackedgeTakenCount);
-  assignSlots(Plan.getPreheader());
+    assignSlotOrName(Plan.BackedgeTakenCount);
+  for (VPValue *LI : Plan.VPLiveInsToFree)
+    assignSlotOrName(LI);
+  assignSlotsOrNames(Plan.getPreheader());
 
   ReversePostOrderTraversal<VPBlockDeepTraversalWrapper<const VPBlockBase *>>
       RPOT(VPBlockDeepTraversalWrapper<const VPBlockBase *>(Plan.getEntry()));
   for (const VPBasicBlock *VPBB :
        VPBlockUtils::blocksOnly<const VPBasicBlock>(RPOT))
-    assignSlots(VPBB);
+    assignSlotsOrNames(VPBB);
 }
 
-void VPSlotTracker::assignSlots(const VPBasicBlock *VPBB) {
+void VPSlotTracker::assignSlotsOrNames(const VPBasicBlock *VPBB) {
   for (const VPRecipeBase &Recipe : *VPBB)
     for (VPValue *Def : Recipe.definedValues())
-      assignSlot(Def);
+      assignSlotOrName(Def);
+}
+
+void VPSlotTracker::deduplicateName(const VPValue *V, StringRef Name) {
+  assert(!Name.empty() && "Name cannot be be empty.");
+  std::string NewName = Name.str();
+  const auto &[A, AssignedInserted] = AssignedNames.insert({V, NewName});
+  if (!AssignedInserted || V->isLiveIn())
+    return;
+
+  const auto &[C, UseInserted] = NameUseCount.insert({NewName, 0});
+  if (!UseInserted) {
+    C->second++;
+    NewName = NewName + "." + std::to_string(C->second);
+    A->second = NewName;
+  }
+}
+
+std::string VPSlotTracker::getName(const VPValue *V) const {
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ayalz wrote:

This does more than retrieve a precomputed name - it also takes part in its final building. Have assignSlotOrName record the final names, to keep its logic in one place and simplify retrieval?

https://github.com/llvm/llvm-project/pull/81411