make hasNUses(0) equivalent to use_empty for constants

Author: arsenm

llvm/lib/IR/Value.cpp

@@ -148,13 +148,19 @@ void Value::destroyValueName() {
 }
 
 bool Value::hasNUses(unsigned N) const {
+  if (!UseList)
+    return N == 0;
+
   // TODO: Disallow for ConstantData and remove !UseList check?
-  return UseList && hasNItems(use_begin(), use_end(), N);
+  return hasNItems(use_begin(), use_end(), N);
 }
 
 bool Value::hasNUsesOrMore(unsigned N) const {
   // TODO: Disallow for ConstantData and remove !UseList check?
-  return UseList && hasNItemsOrMore(use_begin(), use_end(), N);
+  if (!UseList)
+    return N == 0;
+
+  return hasNItemsOrMore(use_begin(), use_end(), N);
 }
 
 bool Value::hasOneUser() const {

llvm/unittests/IR/ConstantsTest.cpp

@@ -29,6 +29,7 @@ TEST(ConstantsTest, UseCounts) {
 
   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));
@@ -49,6 +50,7 @@ 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));