From 0c0e857a6c0c9e758a5433941506c215952a306c Mon Sep 17 00:00:00 2001
From: Simone <91993281+SimoneN64@users.noreply.github.com>
Date: Wed, 22 Jan 2025 10:42:35 +0100
Subject: [PATCH] [JIT]: Constant propagation doesn't need 2 layers + fix JUMP

---
 src/backend/core/jit/instructions.cpp    | 10 ++---
 src/backend/core/registers/Registers.cpp | 48 ++++++++----------------
 2 files changed, 20 insertions(+), 38 deletions(-)

diff --git a/src/backend/core/jit/instructions.cpp b/src/backend/core/jit/instructions.cpp
index 22a1c302..34041400 100644
--- a/src/backend/core/jit/instructions.cpp
+++ b/src/backend/core/jit/instructions.cpp
@@ -10,8 +10,7 @@ using namespace Xbyak::util;
 void JIT::lui(const u32 instr) {
   u64 val = static_cast<s64>(static_cast<s16>(instr));
   val <<= 16;
-  regs.gpr[RT(instr)] = val;
-  regs.gprIsConstant[RT(instr)] = true;
+  regs.Write<s64>(RT(instr), val, true);
 }
 
 void JIT::add(const u32 instr) {
@@ -835,10 +834,9 @@ void JIT::dsubu(u32 instr) {
 
 void JIT::j(const u32 instr) {
   const s32 target = (instr & 0x3ffffff) << 2;
-  code.mov(code.rax, REG(qword, oldPC));
-  code.and_(code.rax, ~0xfffffff);
-  code.or_(code.rax, target);
-  branch_abs(target, mp);
+  const s64 oldPC = branchPC - 8;
+  const s64 address = (oldPC & ~0xfffffff) | target;
+  branch_abs_constant(true, address);
 }
 
 void JIT::jr(const u32 instr) {
diff --git a/src/backend/core/registers/Registers.cpp b/src/backend/core/registers/Registers.cpp
index fa201f98..953e99a0 100644
--- a/src/backend/core/registers/Registers.cpp
+++ b/src/backend/core/registers/Registers.cpp
@@ -126,11 +126,9 @@ void Registers::Write<bool>(size_t idx, bool v, bool isConstant) {
   if (idx == 0)
     return;
 
-  bool oldIsConstant = gprIsConstant[idx];
-  gprIsConstant[idx] = isConstant;
-
   if (jit) {
-    if (oldIsConstant) {
+    gprIsConstant[idx] = isConstant;
+    if (isConstant) {
       gpr[idx] = v;
       return;
     }
@@ -153,11 +151,9 @@ void Registers::Write<u64>(size_t idx, u64 v, bool isConstant) {
   if (idx == 0)
     return;
 
-  bool oldIsConstant = gprIsConstant[idx];
-  gprIsConstant[idx] = isConstant;
-
   if (jit) {
-    if (oldIsConstant) {
+    gprIsConstant[idx] = isConstant;
+    if (isConstant) {
       gpr[idx] = v;
       return;
     }
@@ -185,11 +181,9 @@ void Registers::Write<u32>(size_t idx, u32 v, bool isConstant) {
   if (idx == 0)
     return;
 
-  bool oldIsConstant = gprIsConstant[idx];
-  gprIsConstant[idx] = isConstant;
-
   if (jit) {
-    if (oldIsConstant) {
+    gprIsConstant[idx] = isConstant;
+    if (isConstant) {
       gpr[idx] = v;
       return;
     }
@@ -213,11 +207,9 @@ void Registers::Write<s32>(size_t idx, s32 v, bool isConstant) {
   if (idx == 0)
     return;
 
-  bool oldIsConstant = gprIsConstant[idx];
-  gprIsConstant[idx] = isConstant;
-
   if (jit) {
-    if (oldIsConstant) {
+    gprIsConstant[idx] = isConstant;
+    if (isConstant) {
       gpr[idx] = v;
       return;
     }
@@ -240,11 +232,9 @@ void Registers::Write<u16>(size_t idx, u16 v, bool isConstant) {
   if (idx == 0)
     return;
 
-  bool oldIsConstant = gprIsConstant[idx];
-  gprIsConstant[idx] = isConstant;
-
   if (jit) {
-    if (oldIsConstant) {
+    gprIsConstant[idx] = isConstant;
+    if (isConstant) {
       gpr[idx] = v;
       return;
     }
@@ -268,11 +258,9 @@ void Registers::Write<s16>(size_t idx, s16 v, bool isConstant) {
   if (idx == 0)
     return;
 
-  bool oldIsConstant = gprIsConstant[idx];
-  gprIsConstant[idx] = isConstant;
-
   if (jit) {
-    if (oldIsConstant) {
+    gprIsConstant[idx] = isConstant;
+    if (isConstant) {
       gpr[idx] = v;
       return;
     }
@@ -295,11 +283,9 @@ void Registers::Write<u8>(size_t idx, u8 v, bool isConstant) {
   if (idx == 0)
     return;
 
-  bool oldIsConstant = gprIsConstant[idx];
-  gprIsConstant[idx] = isConstant;
-
   if (jit) {
-    if (oldIsConstant) {
+    gprIsConstant[idx] = isConstant;
+    if (isConstant) {
       gpr[idx] = v;
       return;
     }
@@ -323,11 +309,9 @@ void Registers::Write<s8>(size_t idx, s8 v, bool isConstant) {
   if (idx == 0)
     return;
 
-  bool oldIsConstant = gprIsConstant[idx];
-  gprIsConstant[idx] = isConstant;
-
   if (jit) {
-    if (oldIsConstant) {
+    gprIsConstant[idx] = isConstant;
+    if (isConstant) {
       gpr[idx] = v;
       return;
     }