From 78ea4d20e3cc44e812ab524d73d44d40fef64033 Mon Sep 17 00:00:00 2001
From: Josh warner <jwarner@radio.ecovate.com>
Date: Tue, 11 Aug 2009 13:46:51 -0600
Subject: [PATCH] added loneMatch to improve register allocation

---
 src/compiler.cpp | 40 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/src/compiler.cpp b/src/compiler.cpp
index 0f1f37cdaa..e715f54cce 100644
--- a/src/compiler.cpp
+++ b/src/compiler.cpp
@@ -108,6 +108,8 @@ class Site {
   virtual unsigned copyCost(Context*, Site*) = 0;
 
   virtual bool match(Context*, const SiteMask&) = 0;
+
+  virtual bool loneMatch(Context*, const SiteMask&) = 0;
   
   virtual void acquire(Context*, Value*) { }
 
@@ -1429,6 +1431,10 @@ class ConstantSite: public Site {
     return mask.typeMask & (1 << ConstantOperand);
   }
 
+  virtual bool loneMatch(Context*, const SiteMask&) {
+    return true;
+  }
+
   virtual OperandType type(Context*) {
     return ConstantOperand;
   }
@@ -1501,6 +1507,10 @@ class AddressSite: public Site {
     return mask.typeMask & (1 << AddressOperand);
   }
 
+  virtual bool loneMatch(Context*, const SiteMask&) {
+    return false;
+  }
+
   virtual OperandType type(Context*) {
     return AddressOperand;
   }
@@ -1575,6 +1585,16 @@ class RegisterSite: public Site {
     }
   }
 
+  virtual bool loneMatch(Context* c UNUSED, const SiteMask& mask) {
+    assert(c, number != NoRegister);
+
+    if ((mask.typeMask & (1 << RegisterOperand))) {
+      return ((static_cast<uint64_t>(1) << number) == mask.registerMask);
+    } else {
+      return false;
+    }
+  }
+
   virtual void acquire(Context* c, Value* v) {
     Target target;
     if (number != NoRegister) {
@@ -1729,6 +1749,23 @@ class MemorySite: public Site {
     }
   }
 
+  virtual bool loneMatch(Context* c, const SiteMask& mask) {
+    assert(c, acquired);
+
+    if (mask.typeMask & (1 << MemoryOperand)) {
+      if (base == c->arch->stack()) {
+        assert(c, index == NoRegister);
+
+        if (mask.frameIndex == AnyFrameIndex) {
+          return false;
+        } else {
+          return true;
+        }
+      }
+    }
+    return false;
+  }
+
   virtual void acquire(Context* c, Value* v) {
     increment(c, c->registerResources + base);
     if (index != NoRegister) {
@@ -3145,7 +3182,8 @@ getTarget(Context* c, Value* value, Value* result, const SiteMask& resultMask)
   Site* s;
   Value* v;
   Read* r = liveNext(c, value);
-  if (value->source->match(c, static_cast<const SiteMask&>(resultMask))) {
+  if (value->source->match(c, static_cast<const SiteMask&>(resultMask)) and (r == 0 or 
+          value->source->loneMatch(c, static_cast<const SiteMask&>(resultMask)))) {
     s = value->source;
     v = value;
     if (r and not hasMoreThanOneSite(v)) {