Subzero: Allow delaying Phi lowering until after register allocation.

src/IceInstX8632.cpp

 //===- subzero/src/IceInstX8632.cpp - X86-32 instruction implementation ---===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the InstX8632 and OperandX8632 classes,
@@ skipping 166 matching lines @@
   if (getTargetTrue() == NextNode) {
     assert(Condition != CondX86::Br_None);
     Condition = InstX8632BrAttributes[Condition].Opposite;
     TargetTrue = getTargetFalse();
     TargetFalse = NULL;
     return true;
   }
   return false;
 }
 
+bool InstX8632Br::repointEdge(CfgNode *OldNode, CfgNode *NewNode) {
+  if (TargetFalse == OldNode) {
+    TargetFalse = NewNode;
+    return true;
+  } else if (TargetTrue == OldNode) {
+    TargetTrue = NewNode;
+    return true;
+  }
+  return false;
+}
+
 InstX8632Call::InstX8632Call(Cfg *Func, Variable *Dest, Operand *CallTarget)
     : InstX8632(Func, InstX8632::Call, 1, Dest) {
   HasSideEffects = true;
   addSource(CallTarget);
 }
 
 InstX8632Cmov::InstX8632Cmov(Cfg *Func, Variable *Dest, Operand *Source,
                              CondX86::BrCond Condition)
     : InstX8632(Func, InstX8632::Cmov, 2, Dest), Condition(Condition) {
   // The final result is either the original Dest, or Source, so mark
@@ skipping 2754 matching lines @@
   }
   Str << "(";
   if (Func)
     Var->dump(Func);
   else
     Var->dump(Str);
   Str << ")";
 }
 
 } // end of namespace Ice