[llvm] [DebugInfo][RemoveDIs] Support finding DPValues as well as dbg.values in findDbgValues (PR #71952)

[Orlando Cazalet-Hyams via llvm-commits]

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@@ -78,31 +80,53 @@ static void findDbgIntrinsics(SmallVectorImpl<IntrinsicT *> &Result, Value *V) {
   // V will also appear twice in a dbg.assign if its used in the both the value
   // and address components.
   SmallPtrSet<IntrinsicT *, 4> EncounteredIntrinsics;
+  SmallPtrSet<DPValue *, 4> EncounteredDPValues;
 
   /// Append IntrinsicT users of MetadataAsValue(MD).
-  auto AppendUsers = [&Ctx, &EncounteredIntrinsics, &Result](Metadata *MD) {
+  auto AppendUsers = [&Ctx, &EncounteredIntrinsics, &Result,
+                      DPValues](Metadata *MD) {
     if (auto *MDV = MetadataAsValue::getIfExists(Ctx, MD)) {
       for (User *U : MDV->users())
         if (IntrinsicT *DVI = dyn_cast<IntrinsicT>(U))
           if (EncounteredIntrinsics.insert(DVI).second)
             Result.push_back(DVI);
     }
+    if (!DPValues)
+      return;
+    // Get DPValues that use this as a single value.
+    if (LocalAsMetadata *L = dyn_cast<LocalAsMetadata>(MD)) {
+      for (DPValue *DPV : L->getAllDPValueUsers()) {
+        if (DPV->getType() == DPValue::LocationType::Value)
+          DPValues->push_back(DPV);
+      }
+    }
   };
 
   if (auto *L = LocalAsMetadata::getIfExists(V)) {
     AppendUsers(L);
-    for (Metadata *AL : L->getAllArgListUsers())
+    for (Metadata *AL : L->getAllArgListUsers()) {
       AppendUsers(AL);
+      if (!DPValues)
+        continue;
+      DIArgList *DI = cast<DIArgList>(AL);
+      if (auto *Replaceable = DI->getReplaceableUses()) {
+        for (DPValue *DPV : Replaceable->getAllDPValueUsers())
+          if (DPV->getType() == DPValue::LocationType::Value)
----------------
OCHyams wrote:

There's a template parameter for intrinsic type but not for DPValue type. What do you think of changing the signature to:

```
template <typename IntrinsicT, bool AnyDPVType, DPValue::LocationType SpecificDPVType = DPValue::LocationType(-1)>
static void findDbgIntrinsics(SmallVectorImpl<IntrinsicT *> &Result,
                              Value *V, SmallVectorImpl<DPValue *> *DPValues)
```

Filter DPValeus by `SpecificDPVType` unless `AnyDPVType == true`.

wdyt?

https://github.com/llvm/llvm-project/pull/71952