[turbofan] Fix a bug in the RawMachineAssembler

test/cctest/compiler/test-branch-combine.cc

Index: test/cctest/compiler/test-branch-combine.cc
diff --git a/test/cctest/compiler/test-branch-combine.cc b/test/cctest/compiler/test-branch-combine.cc
index c3b4308a93ed275c54630428687f1acc5386e4f3..11395dbe51b710e454ea3a247a9de159477c39d6 100644
--- a/test/cctest/compiler/test-branch-combine.cc
+++ b/test/cctest/compiler/test-branch-combine.cc
@@ -457,6 +457,41 @@ TEST(BranchCombineFloat64Compares) {
   }
 }
 
+#if V8_TARGET_ARCH_64_BIT
+TEST(BranchCombineWord64EqualZeroPhi) {
+  // Test combining a branch with a Word64Equal between a phi node and 0.
+  RawMachineAssemblerTester<int32_t> m(MachineType::AnyTagged());
+  uintptr_t something = 0x100000000;
+  uintptr_t null = 0;
+
+  Node* p0 = m.Parameter(0);
+
+  RawMachineLabel is_null, is_not_null, merge;
+  m.Branch(m.IntPtrEqual(p0, m.IntPtrConstant(0)), &is_null, &is_not_null);
+  m.Bind(&is_not_null);
+  Node* val = m.Load(MachineType::AnyTagged(), p0);
+  m.Goto(&merge);
+  m.Bind(&is_null);
+  Node* fail_val = m.IntPtrConstant(0);
+  m.Goto(&merge);
+
+  m.Bind(&merge);
+  Node* phi = m.Phi(MachineRepresentation::kTagged, val, fail_val);
+
+  RawMachineLabel pass, fail;
+  m.Branch(m.IntPtrEqual(phi, m.IntPtrConstant(0)), &pass, &fail);
+  m.Bind(&pass);
+  m.Return(m.Int32Constant(0));
+  m.Bind(&fail);
+  m.Return(m.Int32Constant(1));
+
+  CHECK_EQ(1, m.Call(reinterpret_cast<v8::internal::Object*>(&something)));
+  CHECK_EQ(0, m.Call(reinterpret_cast<v8::internal::Object*>(&null)));
+  CHECK_EQ(0, m.Call(static_cast<v8::internal::Object*>(nullptr)));
+}
+
+#endif
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8