[llvm] [LSV] Merge contiguous chains across scalar types (PR #154069)

[via llvm-commits]

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@@ -3496,6 +3496,51 @@ void llvm::copyMetadataForLoad(LoadInst &Dest, const LoadInst &Source) {
   }
 }
 
+void llvm::copyMetadataForStore(StoreInst &Dest, const StoreInst &Source) {
+  SmallVector<std::pair<unsigned, MDNode *>, 8> MD;
+  Source.getAllMetadata(MD);
+  MDBuilder MDB(Dest.getContext());
+  Type *NewType = Dest.getType();
+  for (const auto &MDPair : MD) {
+    unsigned ID = MDPair.first;
+    MDNode *N = MDPair.second;
+    switch (ID) {
+    case LLVMContext::MD_dbg:
+    case LLVMContext::MD_prof:
+    case LLVMContext::MD_tbaa_struct:
+    case LLVMContext::MD_alias_scope:
+    case LLVMContext::MD_noalias:
+    case LLVMContext::MD_nontemporal:
+    case LLVMContext::MD_access_group:
+    case LLVMContext::MD_noundef:
+    case LLVMContext::MD_noalias_addrspace:
+    case LLVMContext::MD_mem_parallel_loop_access:
+      Dest.setMetadata(ID, N);
+      break;
+
+    case LLVMContext::MD_tbaa: {
+      MDNode *NewTyNode =
+          MDB.createTBAAScalarTypeNode(NewType->getStructName(), N);
+      Dest.setMetadata(LLVMContext::MD_tbaa, NewTyNode);
+      break;
+    }
+    case LLVMContext::MD_nonnull:
----------------
LU-JOHN wrote:

The documentation for !nonnull for loads is:

> The optional !nonnull metadata must reference a single metadata name <empty_node> corresponding to a metadata node with no entries. The existence of the !nonnull metadata on the instruction tells the optimizer that the value loaded is known to never be null. If the value is null at runtime, a poison value is returned instead. This is analogous to the nonnull attribute on parameters and return values. This metadata can only be applied to loads of a pointer type.

!nonnull is not documented for stores, but if it is accepted it should mean that the stored value cannot be null.


https://github.com/llvm/llvm-project/pull/154069