From f25611f388e34ec3610a90f8f862cb0ad5679ef9 Mon Sep 17 00:00:00 2001
From: Bram Speeckaert <bram.speeckaert@gmail.com>
Date: Tue, 1 Nov 2022 19:58:27 +0100
Subject: [PATCH] JitArm64: MultiplyImmediate - Handle 1

Multiplication by one is also trivial. Depending on the registers
involved, either a single MOV or no instructions will be generated.

Before:
0x52800038   mov    w24, #0x1
0x1b1a7f1b   mul    w27, w24, w26

After:
0x2a1a03fb   mov    w27, w26

Before:
0x52800039   mov    w25, #0x1
0x1b1a7f3a   mul    w26, w25, w26

After:
Nothing!
---
 Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
index 96e4325106..fb56ce7060 100644
--- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
+++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
@@ -884,6 +884,16 @@ bool JitArm64::MultiplyImmediate(u32 imm, int a, int d, bool rc)
     if (rc)
       ComputeRC0(gpr.GetImm(d));
   }
+  else if (imm == 1)
+  {
+    if (d != a)
+    {
+      gpr.BindToRegister(d, false);
+      MOV(gpr.R(d), gpr.R(a));
+    }
+    if (rc)
+      ComputeRC0(gpr.R(d));
+  }
   else
   {
     // Immediate did not match any known special cases.