[llvm] [DebugInfo][RemoveDIs] Add local-utility plumbing for DPValues (PR #72276)

[Orlando Cazalet-Hyams via llvm-commits]

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@@ -3121,9 +3420,24 @@ void llvm::copyRangeMetadata(const DataLayout &DL, const LoadInst &OldLI,
 
 void llvm::dropDebugUsers(Instruction &I) {
   SmallVector<DbgVariableIntrinsic *, 1> DbgUsers;
-  findDbgUsers(DbgUsers, &I);
-  for (auto *DII : DbgUsers)
-    DII->eraseFromParent();
+  SmallVector<DPValue *, 1> DPUsers;
+  findDbgUsers(DbgUsers, &I, &DPUsers);
+  for (auto *DII : DbgUsers) {
+    if (auto *DbgValue = dyn_cast<DbgValueInst>(DII)) {
+      // Don't delete dbg.values, that's bad.
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OCHyams wrote:

The rest of the patch looks mechanical but this looks like a fix. Was this meant to / should it be a separate patch?

https://github.com/llvm/llvm-project/pull/72276