From a4ba13b4c98f668e69523448960a230c031fea37 Mon Sep 17 00:00:00 2001
From: Sintendo <3380580+Sintendo@users.noreply.github.com>
Date: Sat, 28 Dec 2024 22:12:46 +0100
Subject: [PATCH] JitArm64_Integer: addex - Optimize InHostCarry for -1

Same thing we did for subfex.

Before:
0x1280001a   mov    w26, #-0x1                ; =-1
0x1a1f035a   adc    w26, w26, wzr

After:
0x5a9f23fa   csetm  w26, lo
---
 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 54c86ba1f1..a6820fdfd2 100644
--- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
+++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
@@ -1500,6 +1500,13 @@ void JitArm64::addex(UGeckoInstruction inst)
         // RD = 0 + carry = carry ? 1 : 0
         CSET(RD, CC_CS);
       }
+      else if (is_all_ones)
+      {
+        // RD = -1 + carry = carry ? 0 : -1
+        // Note that CSETM sets the destination to -1 if the condition is true,
+        // and 0 otherwise. Hence, the condition must be carry clear.
+        CSETM(RD, CC_CC);
+      }
       else
       {
         MOVI2R(RD, imm);