Code cleanup for speculative type optimization.

lib/compiler/implementation/ssa/nodes.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 interface HVisitor<R> {
   R visitAdd(HAdd node);
   R visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
   R visitBitOr(HBitOr node);
   R visitBitXor(HBitXor node);
@@ skipping 838 matching lines @@
 
   int getChangesFlags() => flags & ((1 << FLAG_CHANGES_COUNT) - 1);
   bool hasSideEffects() => getChangesFlags() != 0;
   void prepareGvn() { setAllSideEffects(); }
 
   void setAllSideEffects() { flags |= ((1 << FLAG_CHANGES_COUNT) - 1); }
   void clearAllSideEffects() { flags &= ~((1 << FLAG_CHANGES_COUNT) - 1); }
 
   bool useGvn() => getFlag(FLAG_USE_GVN);
   void setUseGvn() { setFlag(FLAG_USE_GVN); }
-  // Does this node pNotentially affect control flow.

[Lasse Reichstein Nielsen, 2012/03/30 12:41:09]

Oh, drat.
Maybe I should reenable window autofocus.

+  // Does this node potentially affect control flow.
   bool isControlFlow() => false;
 
   bool isArray() => type.isArray();
   bool isBoolean() => type.isBoolean();
   bool isInteger() => type.isInteger();
   bool isNumber() => type.isNumber();
   bool isString() => type.isString();
   bool isTypeUnknown() => type.isUnknown();
   bool isStringOrArray() => type.isStringOrArray();
 
   // Compute the type of the instruction.
   HType computeType() => HType.UNKNOWN;
 
-  HType computeDesiredType() {
-    HType candidateType = HType.UNKNOWN;
-    for (final user in usedBy) {
-      HType desiredType = user.computeDesiredInputType(this);
-      if (candidateType.isUnknown()) {
-        candidateType = desiredType;
-      } else if (!type.isUnknown() && candidateType != desiredType) {
-        candidateType = candidateType.combine(desiredType);
-        if (!candidateType.isKnown()) {
-          candidateType = HType.UNKNOWN;
-          break;
-        }
-      }
-    }
-    return candidateType;
-  }
-
   HType computeDesiredInputType(HInstruction input) => HType.UNKNOWN;
 
   // Returns whether the instruction does produce the type it claims.
   // For most instructions, this returns false. A type guard will be
   // inserted to make sure the users get the right type in.
   bool hasExpectedType() => false;
 
   bool isInBasicBlock() => block !== null;
 
   String inputsToString() {
@@ skipping 1201 matching lines @@
 class HIfBlockInformation {
   final HIf branch;
   final SubGraph thenGraph;
   final SubGraph elseGraph;
   final HBasicBlock joinBlock;
   HIfBlockInformation(this.branch,
                       this.thenGraph,
                       this.elseGraph,
                       this.joinBlock);
 }