Prettify !(x rel-op y) into (x "!rel-op" y) when possible.

lib/compiler/implementation/ssa/codegen.dart

 // Copyright (c) 2012, 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.
 
 class SsaCodeGeneratorTask extends CompilerTask {
   SsaCodeGeneratorTask(Compiler compiler) : super(compiler);
   String get name() => 'SSA code generator';
 
 
   String generateMethod(WorkItem work, HGraph graph) {
@@ skipping 1379 matching lines @@
     // With labeled breaks we can have more dominated blocks.
     if (dominated.length >= 3) {
       for (int i = 2; i < dominated.length; i++) {
         visitBasicBlock(dominated[i]);
       }
     }
   }
 
   visitNot(HNot node) {
     assert(node.inputs.length == 1);
+    HInstruction input = node.inputs[0];
+    if (input is HBoolify && isGenerateAtUseSite(input)) {
+      beginExpression(JSPrecedence.EQUALITY_PRECEDENCE);
+      assert(node.inputs.length == 1);
+      use(node.inputs[0], JSPrecedence.EQUALITY_PRECEDENCE);
+      buffer.add(' !== true');
+      endExpression(JSPrecedence.EQUALITY_PRECEDENCE);
+      return;

[ngeoffray, 2012/05/08 09:27:24]

I prefer else if than return.

[Lasse Reichstein Nielsen, 2012/05/08 10:03:33]

Done.

+    }
+    if (input is HRelational &&
+        input.builtin &&
+        isGenerateAtUseSite(input)) {
+      Map<String, String> inverseOperator = const <String>{
+        "==" : "!=",
+        "!=" : "==",
+        "===": "!==",
+        "!==": "===",
+        "<"  : ">=",
+        "<=" : ">",
+        ">"  : "<=",
+        ">=" : "<"
+      };
+      visitInvokeBinary(input,
+                        inverseOperator[input.operation.name.stringValue]);
+      return;

[ngeoffray, 2012/05/08 09:27:24]

ditto.

[Lasse Reichstein Nielsen, 2012/05/08 10:03:33]

Done.

+    }
     beginExpression(JSPrecedence.PREFIX_PRECEDENCE);
     buffer.add('!');
-    use(node.inputs[0], JSPrecedence.PREFIX_PRECEDENCE);
+    use(input, JSPrecedence.PREFIX_PRECEDENCE);
     endExpression(JSPrecedence.PREFIX_PRECEDENCE);
   }
 
   visitParameterValue(HParameterValue node) {
     assert(isGenerateAtUseSite(node));
     buffer.add(parameterNames[node.element]);
   }
 
   visitPhi(HPhi node) {
     String operation = logicalOperations[node];
@@ skipping 816 matching lines @@
       startBailoutSwitch();
     }
   }
 
   void endLabeledBlock(HLabeledBlockInformation labeledBlockInfo) {
     if (labeledBlockInfo.body.start.hasGuards()) {
       endBailoutSwitch();
     }
   }
 }