[DebugInfo] Check DIEnumerator bit width when comparing for equality

[aeubanks]

Summary

As mentioned in D106585, this causes non-determinism, which can also be
shown by this test case being flaky without this patch.

We were using the APSInt's bit width for hashing, but not for checking
for equality. APInt::isSameValue() does not check bit width.

[rnk]

lgtm, thanks for the test!

llvm/lib/IR/LLVMContextImpl.h

template <> struct MDNodeKeyImpl<DIEnumerator> {
   MDNodeKeyImpl(int64_t Value, bool IsUnsigned, MDString *Name)
       : Value(APInt(64, Value, !IsUnsigned)), Name(Name),
         IsUnsigned(IsUnsigned) {}
   MDNodeKeyImpl(const DIEnumerator *N)
       : Value(N->getValue()), Name(N->getRawName()),
         IsUnsigned(N->isUnsigned()) {}
 
   bool isKeyOf(const DIEnumerator *RHS) const {
-    return APInt::isSameValue(Value, RHS->getValue()) &&
-           IsUnsigned == RHS->isUnsigned() && Name == RHS->getRawName();
+    return Value.getBitWidth() == RHS->getValue().getBitWidth() &&
+           Value == RHS->getValue() && IsUnsigned == RHS->isUnsigned() &&
+           Name == RHS->getRawName();
   }
 
   unsigned getHashValue() const { return hash_combine(Value, Name); }
 };
 
 template <> struct MDNodeKeyImpl<DIBasicType> {
   unsigned Tag;
   MDString *Name;

llvm/unittests/IR/DebugInfoTest.cpp

 //===- llvm/unittest/IR/DebugInfo.cpp - DebugInfo tests -------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/IR/DebugInfo.h"
-#include "llvm/IR/DIBuilder.h"
+#include "llvm/ADT/APSInt.h"
 #include "llvm/AsmParser/Parser.h"
+#include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Verifier.h"
 #include "llvm/Support/SourceMgr.h"
 #include "llvm/Transforms/Utils/Local.h"
 #include "gtest/gtest.h"
DIScope *Scope = DISubprogram::getDistinct(
       DINode::FlagZero, DISubprogram::SPFlagZero, nullptr);
   DIType *Type = DIB.createBasicType("Int", 64, dwarf::DW_ATE_signed);
   DIFile *F = DIB.createFile("main.c", "/");
 
   DIDerivedType *SetType = DIB.createSetType(Scope, "set1", F, 1, 64, 64, Type);
   EXPECT_TRUE(isa_and_nonnull<DIDerivedType>(SetType));
 }
 
+TEST(DIBuilder, DIEnumerator) {
+  LLVMContext Ctx;
+  std::unique_ptr<Module> M(new Module("MyModule", Ctx));
+  DIBuilder DIB(*M);
+  APSInt I1(APInt(32, 1));
+  APSInt I2(APInt(33, 1));
+
+  auto *E = DIEnumerator::get(Ctx, I1, I1.isSigned(), "name");
+  EXPECT_TRUE(E);
+
+  auto *E1 = DIEnumerator::getIfExists(Ctx, I1, I1.isSigned(), "name");
+  EXPECT_TRUE(E1);
+
+  auto *E2 = DIEnumerator::getIfExists(Ctx, I2, I1.isSigned(), "name");
+  EXPECT_FALSE(E2);
+}
+
 } // end namespace