dart2js: Constant folding and specialization for remainder

pkg/compiler/lib/src/ssa/value_range_analyzer.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.
 
 import '../compiler.dart' show Compiler;
 import '../constant_system_dart.dart';
 import '../constants/constant_system.dart';
 import '../constants/values.dart';
 import '../js_backend/js_backend.dart';
 import 'nodes.dart';
@@ skipping 669 matching lines @@
     if (!hConstant.isInteger(compiler)) return info.newUnboundRange();
     ConstantValue constant = hConstant.constant;
     NumConstantValue constantNum;
     if (constant is DeferredConstantValue) {
       constantNum = constant.referenced;
     } else {
       constantNum = constant;
     }
     if (constantNum.isPositiveInfinity || constantNum.isNegativeInfinity) {
       return info.newUnboundRange();
-    }
+   }
     if (constantNum.isMinusZero) constantNum = new IntConstantValue(0);
     Value value = info.newIntValue(constantNum.primitiveValue);
     return info.newNormalizedRange(value, value);
   }
 
   Range visitFieldGet(HFieldGet fieldGet) {
     if (!fieldGet.isInteger(compiler)) return info.newUnboundRange();
     if (!fieldGet.receiver.isIndexablePrimitive(compiler)) {
       return visitInstruction(fieldGet);
     }
@@ skipping 124 matching lines @@
           return info.newNormalizedRange(info.intZero, divisor.upper);
         } else if (divisor.isNegative) {
           return info.newNormalizedRange(
               info.intZero, info.newNegateValue(divisor.lower));
         }
       }
     }
     return info.newUnboundRange();
   }
 
+  Range visitRemainder(HRemainder instruction) {
+    HInstruction left = instruction.inputs[0];
+    HInstruction right = instruction.inputs[1];
+    if (left.isPositiveInteger(compiler) && right.isPositiveInteger(compiler)) {
+      Range divisor = ranges[right];
+      if (divisor != null) {
+        if (divisor.isPositive) {
+          return info.newNormalizedRange(
+              info.intZero, divisor.upper - info.intOne);
+        }
+      }
+    }
+    return info.newUnboundRange();
+  }
+
   Range visitInvokeDynamicMethod(HInvokeDynamicMethod invoke) {
     if ((invoke.inputs.length == 3) && (invoke.selector.name == "%"))
       return handleInvokeModulo(invoke);
     return super.visitInvokeDynamicMethod(invoke);
   }
 
   Range handleBinaryOperation(HBinaryArithmetic instruction) {
     if (!instruction.isInteger(compiler)) return info.newUnboundRange();
     return instruction
         .operation(constantSystem)
@@ skipping 234 matching lines @@
   }
 
   Range handleBinaryOperation(HBinaryArithmetic instruction) {
     Range leftRange = visit(instruction.left);
     Range rightRange = visit(instruction.right);
     if (leftRange == null || rightRange == null) return null;
     BinaryOperation operation = instruction.operation(info.constantSystem);
     return operation.apply(leftRange, rightRange);
   }
 }