Merge pull request #9817 from Sintendo/jit64subfic

Jit64: subfic - Optimize constants for d != a
dolphin-emu · Jun 17, 2021 · b530d9b · b530d9b
2 parents 4e9e75f + 18aaf48
commit b530d9b
Showing 1 changed file with 24 additions and 21 deletions.
diff --git a/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp b/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp
@@ -898,28 +898,31 @@ void Jit64::subfic(UGeckoInstruction inst)
   RCX64Reg Rd = gpr.Bind(d, RCMode::Write);
   RegCache::Realize(Ra, Rd);
 
-  if (d == a)
+  if (imm == 0)
   {
-    if (imm == 0)
-    {
-      // Flags act exactly like subtracting from 0
-      NEG(32, Rd);
-      // Output carry is inverted
-      FinalizeCarry(CC_NC);
-    }
-    else if (imm == -1)
-    {
-      NOT(32, Rd);
-      // CA is always set in this case
-      FinalizeCarry(true);
-    }
-    else
-    {
-      NOT(32, Rd);
-      ADD(32, Rd, Imm32(imm + 1));
-      // Output carry is normal
-      FinalizeCarry(CC_C);
-    }
+    if (d != a)
+      MOV(32, Rd, Ra);
+
+    // Flags act exactly like subtracting from 0
+    NEG(32, Rd);
+    // Output carry is inverted
+    FinalizeCarry(CC_NC);
+  }
+  else if (imm == -1)
+  {
+    if (d != a)
+      MOV(32, Rd, Ra);
+
+    NOT(32, Rd);
+    // CA is always set in this case
+    FinalizeCarry(true);
+  }
+  else if (d == a)
+  {
+    NOT(32, Rd);
+    ADD(32, Rd, Imm32(imm + 1));
+    // Output carry is normal
+    FinalizeCarry(CC_C);
   }
   else
   {