[llvm] IR: Remove null UseList checks in hasNUses methods (PR #165929)

[Nikita Popov via llvm-commits]

================
@@ -50,15 +45,36 @@ TEST(ConstantsTest, UseCounts) {
   // Still looks like use_empty with uses.
   EXPECT_TRUE(Zero->use_empty());
   EXPECT_EQ(Zero->getNumUses(), 0u);
-  EXPECT_TRUE(Zero->hasNUses(0));
   EXPECT_FALSE(Zero->hasOneUse());
   EXPECT_FALSE(Zero->hasOneUser());
-  EXPECT_FALSE(Zero->hasNUses(1));
-  EXPECT_FALSE(Zero->hasNUsesOrMore(1));
-  EXPECT_FALSE(Zero->hasNUses(2));
-  EXPECT_FALSE(Zero->hasNUsesOrMore(2));
 }
 
+#ifdef GTEST_HAS_DEATH_TEST
+#ifndef NDEBUG
+
+TEST(ConstantsTest, hasNUsesInvalid) {
+  LLVMContext Context;
+  Type *Int32Ty = Type::getInt32Ty(Context);
+  Constant *Zero = ConstantInt::get(Int32Ty, 0);
+  std::unique_ptr<Module> M(new Module("MyModule", Context));
+
+  // Introduce some uses
+  new GlobalVariable(*M, Int32Ty, /*isConstant=*/false,
+                     GlobalValue::ExternalLinkage, /*Initializer=*/Zero,
+                     "gv_user0");
+  new GlobalVariable(*M, Int32Ty, /*isConstant=*/false,
+                     GlobalValue::ExternalLinkage, /*Initializer=*/Zero,
+                     "gv_user1");
+
+  for (int I = 0; I != 3; ++I) {
+    EXPECT_DEATH(Zero->hasNUses(I), "hasUseList()");
+    EXPECT_DEATH(Zero->hasNUsesOrMore(I), "hasUseList()");
----------------
nikic wrote:

```suggestion
    EXPECT_DEATH(Zero->hasNUses(I), "hasUseList\(\)");
    EXPECT_DEATH(Zero->hasNUsesOrMore(I), "hasUseList\(\)");
```

https://github.com/llvm/llvm-project/pull/165929