[IR] Provide array with poison-generating metadata IDs. (#123188)

Add Metadata::PoisonGeneratingIDs containing IDs of poison-generating
metadata to allow easier re-use.

PR: #123188

Author: fhahn

llvm/include/llvm/IR/Metadata.h

@@ -138,6 +138,10 @@ class Metadata {
   void printAsOperand(raw_ostream &OS, ModuleSlotTracker &MST,
                       const Module *M = nullptr) const;
   /// @}
+
+  /// Metadata IDs that may generate poison.
+  constexpr static const unsigned PoisonGeneratingIDs[] = {
+      LLVMContext::MD_range, LLVMContext::MD_nonnull, LLVMContext::MD_align};
 };
 
 // Create wrappers for C Binding types (see CBindingWrapping.h).

llvm/lib/IR/Instruction.cpp

@@ -458,9 +458,8 @@ void Instruction::dropPoisonGeneratingFlags() {
 }
 
 bool Instruction::hasPoisonGeneratingMetadata() const {
-  return hasMetadata(LLVMContext::MD_range) ||
-         hasMetadata(LLVMContext::MD_nonnull) ||
-         hasMetadata(LLVMContext::MD_align);
+  return any_of(Metadata::PoisonGeneratingIDs,
+                [this](unsigned ID) { return hasMetadata(ID); });
 }
 
 bool Instruction::hasNonDebugLocLoopMetadata() const {
@@ -487,9 +486,8 @@ bool Instruction::hasNonDebugLocLoopMetadata() const {
 }
 
 void Instruction::dropPoisonGeneratingMetadata() {
-  eraseMetadata(LLVMContext::MD_range);
-  eraseMetadata(LLVMContext::MD_nonnull);
-  eraseMetadata(LLVMContext::MD_align);
+  for (unsigned ID : Metadata::PoisonGeneratingIDs)
+    eraseMetadata(ID);
 }
 
 bool Instruction::hasPoisonGeneratingReturnAttributes() const {

llvm/lib/Transforms/IPO/ArgumentPromotion.cpp

@@ -259,8 +259,7 @@ doPromotion(Function *F, FunctionAnalysisManager &FAM,
             // all promoted loads.
             if (LI->hasMetadata(LLVMContext::MD_noundef))
               LI->copyMetadata(*Pair.second.MustExecInstr,
-                               {LLVMContext::MD_range, LLVMContext::MD_nonnull,
-                                LLVMContext::MD_align});
+                               Metadata::PoisonGeneratingIDs);
           }
           Args.push_back(LI);
           ArgAttrVec.push_back(AttributeSet());