[llvm] Reland "[ThinLTO][Bitcode] Generate import type in bitcode" (PR #97253)

[Jan Voung via llvm-commits]

================
@@ -1277,7 +1278,7 @@ using ModulePathStringTableTy = StringMap<ModuleHash>;
 using GVSummaryMapTy = DenseMap<GlobalValue::GUID, GlobalValueSummary *>;
 
 /// A set of global value summary pointers.
-using GVSummaryPtrSet = SmallPtrSet<GlobalValueSummary *, 4>;
+using GVSummaryPtrSet = std::unordered_set<GlobalValueSummary *>;
----------------
jvoung wrote:

Ah nice -- interesting that SmallPtrSet also has a big jump when growing at small sizes! (https://github.com/llvm/llvm-project/blob/393eff4e02e7ab3d234d246a8d6912c8e745e6f9/llvm/lib/Support/SmallPtrSet.cpp#L43)

https://github.com/llvm/llvm-project/pull/97253