[llvm] [HLSL] Analyze update counter usage (PR #130356)

[Ashley Coleman via llvm-commits]

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@@ -823,8 +827,153 @@ DXILBindingMap::findByUse(const Value *Key) const {
 
 //===----------------------------------------------------------------------===//
 
+static bool isUpdateCounterIntrinsic(Function &F) {
+  return F.getIntrinsicID() == Intrinsic::dx_resource_updatecounter;
+}
+
+void DXILResourceCounterDirectionMap::populate(Module &M, DXILBindingMap &DBM) {
+  std::vector<std::tuple<dxil::ResourceBindingInfo, ResourceCounterDirection,
+                         const Function *, const CallInst *>>
+      DiagCounterDirs;
+
+  for (Function &F : M.functions()) {
+    if (!isUpdateCounterIntrinsic(F))
+      continue;
+
+    for (const User *U : F.users()) {
+      const CallInst *CI = dyn_cast<CallInst>(U);
+      assert(CI && "Users of dx_resource_updateCounter must be call instrs");
+
+      // Determine if the use is an increment or decrement
+      Value *CountArg = CI->getArgOperand(1);
+      ConstantInt *CountValue = dyn_cast<ConstantInt>(CountArg);
+      int64_t CountLiteral = CountValue->getSExtValue();
+
+      ResourceCounterDirection Direction = ResourceCounterDirection::Unknown;
+      if (CountLiteral > 0)
+        Direction = ResourceCounterDirection::Increment;
+      if (CountLiteral < 0)
+        Direction = ResourceCounterDirection::Decrement;
+
+      // Collect all potential creation points for the handle arg
+      Value *HandleArg = CI->getArgOperand(0);
+      SmallVector<dxil::ResourceBindingInfo> RBInfos = DBM.findByUse(HandleArg);
+      for (const dxil::ResourceBindingInfo RBInfo : RBInfos)
+        DiagCounterDirs.emplace_back(RBInfo, Direction, &F, CI);
+    }
+  }
+
+  // An entry that is not in the map is considered unknown so its wasted
+  // overhead and increased complexity to keep an entry explicitly marked
+  // unknown
+  const auto RemoveEnd = std::remove_if(
+      DiagCounterDirs.begin(), DiagCounterDirs.end(), [](const auto &Item) {
+        return std::get<ResourceCounterDirection>(Item) ==
+               ResourceCounterDirection::Unknown;
+      });
+
+  // Sort by the Binding and Direction for fast lookup
+  std::sort(DiagCounterDirs.begin(), RemoveEnd,
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V-FEXrt wrote:

`stable_sort` is no longer needed not that we raise the Diag for every call.

https://github.com/llvm/llvm-project/pull/130356