[llvm] Compute GUIDs once and store in metadata (PR #184065)

[Mircea Trofin via llvm-commits]

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@@ -576,7 +577,22 @@ class LLVM_ABI Module {
   // Use global_size() to get the total number of global variables.
   // Use globals() to get the range of all global variables.
 
+  std::optional<GlobalValue::GUID> getGUID(const Value* V) const {
+    const auto It = ValueToGUIDMap.find(V);
+    if (It == ValueToGUIDMap.end()) {
+      return {};
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mtrofin wrote:

nit: return std::nullopt?

https://github.com/llvm/llvm-project/pull/184065