From 21c26052989f6f8c29c6670c40f35df84638d12b Mon Sep 17 00:00:00 2001
From: Sintendo <3380580+Sintendo@users.noreply.github.com>
Date: Fri, 27 Mar 2026 00:54:56 +0100
Subject: [PATCH] JitArm64_Integer: subfzex - Optimize a == -1 with in-host
 carry

Before:
0x12800019   mov    w25, #-0x1                ; =-1
0x7a1903fa   ngcs   w26, w25
0x1a9f37f8   cset   w24, hs
0x390bd3b8   strb   w24, [x29, #0x2f4]

After:
0x1a9f37fa   cset   w26, hs
---
 Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
index 3cf4175b72..d60a499594 100644
--- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
+++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
@@ -1335,6 +1335,13 @@ void JitArm64::subfzex(UGeckoInstruction inst)
     CSETM(gpr.R(d), CC_CC);
     // Carry remains unchanged.
   }
+  else if (gpr.IsImm(a, 0xFFFFFFFF) && js.carryFlag == CarryFlag::InHostCarry)
+  {
+    gpr.BindToRegister(d, false);
+    // RD = ~(-1) + carry = 0 + carry = carry ? 1 : 0
+    CSET(gpr.R(d), CC_CS);
+    ComputeCarry(false);
+  }
   else
   {
     gpr.BindToRegister(d, d == a);