Add an early `TailMerge` pass (#2721)

* Add an early `TailMerge` pass

Some translations can have a lot of guest calls and since for each guest
call there is a call guard which may return. This can produce a lot of
epilogue code for returns. This pass merges the epilogue into a single
block.

```
Using filter 'hcq'.
Using metric 'code size'.

Total diff: -1648111 (-7.19 %) (bytes):
  Base: 22913847
  Diff: 21265736

Improved: 4567, regressed: 14, unchanged: 144
```

* Set PTC version

* Address feedback

* Handle `void` returning functions

* Actually handle `void` returning functions

* Fix `RegisterToLocal` logging

1 files changed, 22 insertions, 11 deletions

diff --git a/ARMeilleure/Translation/Compiler.cs b/ARMeilleure/Translation/Compiler.cs
index 9e4cdb24..817bd487 100644
--- a/ARMeilleure/Translation/Compiler.cs
+++ b/ARMeilleure/Translation/Compiler.cs
@@ -1,4 +1,5 @@
 using ARMeilleure.CodeGen;
+using ARMeilleure.CodeGen.Optimizations;
 using ARMeilleure.CodeGen.X86;
 using ARMeilleure.Diagnostics;
 using ARMeilleure.IntermediateRepresentation;
@@ -13,30 +14,40 @@ namespace ARMeilleure.Translation
             OperandType      retType,
             CompilerOptions  options)
         {
-            Logger.StartPass(PassName.Dominance);
+            CompilerContext cctx = new(cfg, argTypes, retType, options);
+
+            if (options.HasFlag(CompilerOptions.Optimize))
+            {
+                Logger.StartPass(PassName.TailMerge);
+
+                TailMerge.RunPass(cctx);
 
-            if ((options & CompilerOptions.SsaForm) != 0)
+                Logger.EndPass(PassName.TailMerge, cfg);
+            }
+
+            if (options.HasFlag(CompilerOptions.SsaForm))
             {
+                Logger.StartPass(PassName.Dominance);
+
                 Dominance.FindDominators(cfg);
                 Dominance.FindDominanceFrontiers(cfg);
-            }
 
-            Logger.EndPass(PassName.Dominance);
+                Logger.EndPass(PassName.Dominance);
 
-            Logger.StartPass(PassName.SsaConstruction);
+                Logger.StartPass(PassName.SsaConstruction);
 
-            if ((options & CompilerOptions.SsaForm) != 0)
-            {
                 Ssa.Construct(cfg);
+
+                Logger.EndPass(PassName.SsaConstruction, cfg);
             }
             else
             {
-                RegisterToLocal.Rename(cfg);
-            }
+                Logger.StartPass(PassName.RegisterToLocal);
 
-            Logger.EndPass(PassName.SsaConstruction, cfg);
+                RegisterToLocal.Rename(cfg);
 
-            CompilerContext cctx = new(cfg, argTypes, retType, options);
+                Logger.EndPass(PassName.RegisterToLocal, cfg);
+            }
 
             return CodeGenerator.Generate(cctx);
         }