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

[via llvm-commits]

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@@ -1112,6 +1123,26 @@ VPlan *VPlan::duplicate() {
   return NewPlan;
 }
 
+void VPlan::setName(const VPValue *V, const Twine &Name) {
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+  std::string N = Name.str();
+  if (N.empty())
+    return;
+  assert(!VPValue2Name.contains(V));
+  std::string CurrName = N;
+
+  if (UsedNames.contains(N))
+    CurrName = N + ".1";
+  unsigned Cnt = 2;
+  while (UsedNames.contains(CurrName)) {
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ayalz wrote:

This O(n^2) search is tolerable because n is expected to be very small? Can alternatively hold a map between used names and the number of times each name is used, instead of a set. The former will avoid reusing names that were removed.

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