Fix the dirty bit and make the register cache use it to be a bit more clever:

it skips storing a register back to memory if its value hasn't changed. 
This happens with stuff like compares and fast memory loads.

This is the first in a series of enhancements I have in my tree for the 
jit that I plan to commit over the next few hours.  I'm likely to 
cause some breakage, so if you see regrassions, please report them; if 
you can track them down to a specific revision, that would be very 
helpful.  I'm trying to make the changes small to allow pinpointing 
regressions more easily.



git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@1252 8ced0084-cf51-0410-be5f-012b33b47a6e

1 files changed, 6 insertions, 2 deletions

diff --git a/Source/Core/Core/Src/PowerPC/Jit64/JitRegCache.cpp b/Source/Core/Core/Src/PowerPC/Jit64/JitRegCache.cpp
index 645475d92e..2392f22dd3 100644
--- a/Source/Core/Core/Src/PowerPC/Jit64/JitRegCache.cpp
+++ b/Source/Core/Core/Src/PowerPC/Jit64/JitRegCache.cpp
@@ -198,6 +198,7 @@ namespace Jit64
 		if (regs[preg].away && regs[preg].location.IsSimpleReg())

 		{

 			xregs[regs[preg].location.GetSimpleReg()].free = true;

+			xregs[regs[preg].location.GetSimpleReg()].dirty = false;

 			regs[preg].away = false;

 		}

 	}

@@ -291,7 +292,7 @@ namespace Jit64
 			if (xlocks[xr]) PanicAlert("GetFreeXReg returned locked register");

 			xregs[xr].free = false;

 			xregs[xr].ppcReg = i;

-			xregs[xr].dirty = makeDirty;

+			xregs[xr].dirty = makeDirty || regs[i].location.IsImm();

 			OpArg newloc = ::Gen::R(xr);

 			if (doLoad || regs[i].location.IsImm())

 				MOV(32, newloc, regs[i].location);

@@ -321,11 +322,13 @@ namespace Jit64
 	{

 		if (regs[i].away)

 		{

+			bool doStore = true;

 			if (regs[i].location.IsSimpleReg())

 			{

 				X64Reg xr = RX(i);

 				xregs[xr].free = true;

 				xregs[xr].ppcReg = -1;

+				doStore = xregs[xr].dirty;

 				xregs[xr].dirty = false;

 			}

 			else

@@ -333,7 +336,8 @@ namespace Jit64
 				//must be immediate - do nothing

 			}

 			OpArg newLoc = GetDefaultLocation(i);

-			MOV(32, newLoc, regs[i].location);

+			if (doStore)

+				MOV(32, newLoc, regs[i].location);

 			regs[i].location = newLoc;

 			regs[i].away = false;

 		}