From ad7dba541353d532f0299f6442e8ca59a9040695 Mon Sep 17 00:00:00 2001
From: Sintendo <3380580+Sintendo@users.noreply.github.com>
Date: Sat, 28 Dec 2024 21:41:48 +0100
Subject: [PATCH] JitArm64_Integer: addex - Optimize InPPCState case for 0

Same optimization we did for subfex. Skip loading the carry flag into a
temporary register first when we're dealing with zero.

Before:
0x394bd3b8   ldrb   w24, [x29, #0x2f4]
0x2a1803f9   mov    w25, w24

After:
0x394bd3b9   ldrb   w25, [x29, #0x2f4]
---
 .../PowerPC/JitArm64/JitArm64_Integer.cpp     | 31 +++++++++++++------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
index b2193faf36..eb742ac1dd 100644
--- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
+++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
@@ -1468,40 +1468,51 @@ void JitArm64::addex(UGeckoInstruction inst)
 
   if (gpr.IsImm(a) && (mex || gpr.IsImm(b)))
   {
-    u32 i = gpr.GetImm(a), j = mex ? -1 : gpr.GetImm(b);
-
-    gpr.BindToRegister(d, false);
+    const u32 i = gpr.GetImm(a), j = mex ? -1 : gpr.GetImm(b);
+    const u32 imm = i + j;
+    const bool is_zero = imm == 0;
+    const bool is_all_ones = imm == 0xFFFFFFFF;
 
     switch (js.carryFlag)
     {
     case CarryFlag::InPPCState:
     {
-      auto WA = gpr.GetScopedReg();
-      LDRB(IndexType::Unsigned, WA, PPC_REG, PPCSTATE_OFF(xer_ca));
-      ADDI2R(gpr.R(d), WA, i + j, gpr.R(d));
+      gpr.BindToRegister(d, false);
+      ARM64Reg RD = gpr.R(d);
+      if (is_zero)
+      {
+        LDRB(IndexType::Unsigned, RD, PPC_REG, PPCSTATE_OFF(xer_ca));
+      }
+      else
+      {
+        auto WA = gpr.GetScopedReg();
+        LDRB(IndexType::Unsigned, WA, PPC_REG, PPCSTATE_OFF(xer_ca));
+        ADDI2R(RD, WA, imm, RD);
+      }
       break;
     }
     case CarryFlag::InHostCarry:
     {
+      gpr.BindToRegister(d, false);
       ARM64Reg RD = gpr.R(d);
-      MOVI2R(RD, i + j);
+      MOVI2R(RD, imm);
       ADC(RD, RD, ARM64Reg::WZR);
       break;
     }
     case CarryFlag::ConstantTrue:
     {
-      gpr.SetImmediate(d, i + j + 1);
+      gpr.SetImmediate(d, imm + 1);
       break;
     }
     case CarryFlag::ConstantFalse:
     {
-      gpr.SetImmediate(d, i + j);
+      gpr.SetImmediate(d, imm);
       break;
     }
     }
 
     const bool must_have_carry = Interpreter::Helper_Carry(i, j);
-    const bool might_have_carry = (i + j) == 0xFFFFFFFF;
+    const bool might_have_carry = is_all_ones;
 
     if (must_have_carry)
     {