[llvm] [AMDGPU] Propagate alias information in AMDGPULowerKernelArguments. (PR #161375)

[Leon Clark via llvm-commits]

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@@ -58,6 +66,143 @@ static BasicBlock::iterator getInsertPt(BasicBlock &BB) {
   return InsPt;
 }
 
+static void addAliasScopeMetadata(Function &F, DataLayout const &DL) {
+  // Collect noalias arguments.
+  auto NoAliasArgs = SmallVector<Argument const *, 4u>();
+
+  for (auto &Arg : F.args())
+    if (Arg.hasNoAliasAttr() && !Arg.use_empty())
+      NoAliasArgs.push_back(&Arg);
+
+  if (NoAliasArgs.empty())
+    return;
+
+  // Add alias scopes for each noalias argument.
+  auto MDB = MDBuilder(F.getContext());
+  auto NewScopes = DenseMap<Argument const *, MDNode *>();
+  auto *NewDomain = MDB.createAnonymousAliasScopeDomain(F.getName());
+
+  for (auto I = 0u; I < NoAliasArgs.size(); ++I) {
+    auto *Arg = NoAliasArgs[I];
+    auto Name = std::string(F.getName());
+
+    if (Arg->hasName())
+      Name += std::string(": %") + std::string(Arg->getName());
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PeddleSpam wrote:

This was based on similar code in [InlineFunction.cpp](https://github.com/llvm/llvm-project/blob/6459f39c377dc8b7d5d81ef365553c8625fb4def/llvm/lib/Transforms/Utils/InlineFunction.cpp#L1152).

https://github.com/llvm/llvm-project/pull/161375