From e41f0d9dec258297d62e649bd939a23a50e6f998 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sun, 12 Nov 2023 14:42:37 +0100
Subject: [PATCH] LibJS/JIT: Add fast path for loose equality check between 2
 objects

There are more fast paths to be added here, just starting with this
one since it's heavy on Kraken/ai-astar.js :^)
---
 Userland/Libraries/LibJS/JIT/Compiler.cpp | 45 +++++++++++++++++++++++
 Userland/Libraries/LibJS/JIT/Compiler.h   |  1 -
 2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/Userland/Libraries/LibJS/JIT/Compiler.cpp b/Userland/Libraries/LibJS/JIT/Compiler.cpp
index d332e369dc..9097e00ff8 100644
--- a/Userland/Libraries/LibJS/JIT/Compiler.cpp
+++ b/Userland/Libraries/LibJS/JIT/Compiler.cpp
@@ -618,6 +618,51 @@ static ThrowCompletionOr<Value> strict_equals(VM&, Value src1, Value src2)
     return Value(is_strictly_equal(src1, src2));
 }
 
+static Value cxx_loosely_equals(VM& vm, Value lhs, Value rhs)
+{
+    return TRY_OR_SET_EXCEPTION(loosely_equals(vm, lhs, rhs));
+}
+
+void Compiler::compile_loosely_equals(Bytecode::Op::LooselyEquals const& op)
+{
+    Assembler::Label end;
+
+    load_vm_register(ARG1, op.lhs());
+    load_accumulator(ARG2);
+
+    // Fast path if both sides are objects.
+    branch_if_object(ARG1, [&] {
+        branch_if_object(ARG2, [&] {
+            Assembler::Label true_case;
+
+            m_assembler.jump_if(
+                Assembler::Operand::Register(ARG1),
+                Assembler::Condition::EqualTo,
+                Assembler::Operand::Register(ARG2),
+                true_case);
+
+            m_assembler.mov(
+                Assembler::Operand::Register(GPR0),
+                Assembler::Operand::Imm(Value(false).encoded()));
+            store_accumulator(GPR0);
+            m_assembler.jump(end);
+
+            true_case.link(m_assembler);
+            m_assembler.mov(
+                Assembler::Operand::Register(GPR0),
+                Assembler::Operand::Imm(Value(true).encoded()));
+            store_accumulator(GPR0);
+            m_assembler.jump(end);
+        });
+    });
+
+    native_call((void*)cxx_loosely_equals);
+    store_accumulator(RET);
+    check_exception();
+
+    end.link(m_assembler);
+}
+
 #    define DO_COMPILE_COMMON_BINARY_OP(TitleCaseName, snake_case_name)                 \
         static Value cxx_##snake_case_name(VM& vm, Value lhs, Value rhs)                \
         {                                                                               \
diff --git a/Userland/Libraries/LibJS/JIT/Compiler.h b/Userland/Libraries/LibJS/JIT/Compiler.h
index ae14ae046a..32a883c085 100644
--- a/Userland/Libraries/LibJS/JIT/Compiler.h
+++ b/Userland/Libraries/LibJS/JIT/Compiler.h
@@ -51,7 +51,6 @@ private:
         O(In, in)                                               \
         O(InstanceOf, instance_of)                              \
         O(LooselyInequals, loosely_inequals)                    \
-        O(LooselyEquals, loosely_equals)                        \
         O(StrictlyInequals, strict_inequals)                    \
         O(StrictlyEquals, strict_equals)