[Verifier] Only allow invariant.group metadata on stores and loads

[aeubanks]

Summary

As specified by https://llvm.org/docs/LangRef.html#invariant-group-metadata.

[aeubanks]

update

llvm/lib/IR/Verifier.cpp

void Verifier::visitInstruction(Instruction &I) {
   }
 
   if (MDNode *Range = I.getMetadata(LLVMContext::MD_range)) {
     Assert(isa<LoadInst>(I) || isa<CallInst>(I) || isa<InvokeInst>(I),
            "Ranges are only for loads, calls and invokes!", &I);
     visitRangeMetadata(I, Range, I.getType());
   }
 
+  if (I.hasMetadata(LLVMContext::MD_invariant_group)) {
+    Assert(isa<LoadInst>(I) || isa<StoreInst>(I),
+           "invariant.group metadata is only for loads and stores", &I);
+  }
+
   if (I.getMetadata(LLVMContext::MD_nonnull)) {
     Assert(I.getType()->isPointerTy(), "nonnull applies only to pointer types",
            &I);
     Assert(isa<LoadInst>(I),
            "nonnull applies only to load instructions, use attributes"
            " for calls or invokes",
            &I);
   }

llvm/test/Verifier/invariant.group.ll

+; RUN: not opt -passes=verify -disable-output < %s 2>&1 | FileCheck %s
+
+; CHECK: invariant.group metadata is only for loads and stores
+; CHECK-NEXT: alloca
+; CHECK-NEXT: invariant.group metadata is only for loads and stores
+; CHECK-NEXT: ret void
+define void @f() {
+  %a = alloca i32, !invariant.group !0
+  %b = load i32, i32* %a, !invariant.group !0
+  store i32 43, i32* %a, !invariant.group !0
+  ret void, !invariant.group !0
+}
+
+!0 = !{}