dart2js cps: Support --trust-primitives and --trust-type-annotations.

pkg/compiler/lib/src/cps_ir/type_propagation.dart

Index: pkg/compiler/lib/src/cps_ir/type_propagation.dart
diff --git a/pkg/compiler/lib/src/cps_ir/type_propagation.dart b/pkg/compiler/lib/src/cps_ir/type_propagation.dart
index 4748a59621bc931528b63d1b7e8d45ce5417427c..73b2e63621a6b2c0f73f66ee84ef20387c0d4b54 100644
--- a/pkg/compiler/lib/src/cps_ir/type_propagation.dart
+++ b/pkg/compiler/lib/src/cps_ir/type_propagation.dart
@@ -984,6 +984,8 @@ class TransformingVisitor extends DeepRecursiveVisitor {
               operator, <Primitive>[argument], node.sourceInformation));
     }
 
+    bool trustPrimitives = compiler.trustPrimitives;
+
     if (node.selector.isOperator && node.arguments.length == 2) {
       Primitive leftArg = getDartReceiver(node);
       Primitive rightArg = getDartArgument(node, 0);
@@ -1016,8 +1018,8 @@ class TransformingVisitor extends DeepRecursiveVisitor {
                                    leftArg, rightArg);
         }
       } else {
-        if (lattice.isDefinitelyNum(left, allowNull: false) &&
-            lattice.isDefinitelyNum(right, allowNull: false)) {
+        if (lattice.isDefinitelyNum(left, allowNull: trustPrimitives) &&
+            lattice.isDefinitelyNum(right, allowNull: trustPrimitives)) {
           // Try to insert a numeric operator.
           BuiltinOperator operator = NumBinaryBuiltins[opname];
           if (operator != null) {
@@ -1028,7 +1030,7 @@ class TransformingVisitor extends DeepRecursiveVisitor {
           // shift count.
           // Try to insert a shift-left operator.
           if (opname == '<<' &&
-              lattice.isDefinitelyInt(left) &&
+              lattice.isDefinitelyInt(left, allowNull: trustPrimitives) &&
               lattice.isDefinitelyIntInRange(right, min: 0, max: 31)) {
             return replaceWithBinary(BuiltinOperator.NumShl, leftArg, rightArg);
           }
@@ -1036,14 +1038,14 @@ class TransformingVisitor extends DeepRecursiveVisitor {
           // consistent with Dart's only for left operands in the unsigned
           // 32-bit range.
           if (opname == '>>' &&
-              lattice.isDefinitelyUint32(left) &&
+              lattice.isDefinitelyUint32(left, allowNull: trustPrimitives) &&
               lattice.isDefinitelyIntInRange(right, min: 0, max: 31)) {
             return replaceWithBinary(BuiltinOperator.NumShr, leftArg, rightArg);
           }
           // Try to use remainder for '%'. Both operands must be non-negative
           // and the divisor must be non-zero.
           if (opname == '%' &&
-              lattice.isDefinitelyUint(left) &&
+              lattice.isDefinitelyUint(left, allowNull: trustPrimitives) &&
               lattice.isDefinitelyUint(right) &&
               lattice.isDefinitelyIntInRange(right, min: 1)) {
             return replaceWithBinary(
@@ -1051,15 +1053,15 @@ class TransformingVisitor extends DeepRecursiveVisitor {
           }
 
           if (opname == '~/' &&
-              lattice.isDefinitelyUint32(left) &&
+              lattice.isDefinitelyUint32(left, allowNull: trustPrimitives) &&
               lattice.isDefinitelyIntInRange(right, min: 2)) {
             return replaceWithBinary(
                 BuiltinOperator.NumTruncatingDivideToSigned32,
                 leftArg, rightArg);
           }
         }
-        if (lattice.isDefinitelyString(left, allowNull: false) &&
-            lattice.isDefinitelyString(right, allowNull: false) &&
+        if (lattice.isDefinitelyString(left, allowNull: trustPrimitives) &&
+            lattice.isDefinitelyString(right, allowNull: trustPrimitives) &&
             opname == '+') {
           return replaceWithBinary(BuiltinOperator.StringConcatenate,
                                    leftArg, rightArg);
@@ -1173,6 +1175,9 @@ class TransformingVisitor extends DeepRecursiveVisitor {
                               Primitive index,
                               SourceInformation sourceInfo) {
     CpsFragment cps = new CpsFragment(sourceInfo);
+    if (compiler.trustPrimitives) {
+      return cps;
+    }
     Continuation fail = cps.letCont();
     Primitive isTooSmall = cps.applyBuiltin(
         BuiltinOperator.NumLt,
@@ -2971,7 +2976,7 @@ class TypePropagationVisitor implements Visitor {
       // own bounds-check elimination?
       setValue(node, constantValue(new IntConstantValue(length)));
     } else {
-      setValue(node, nonConstant(typeSystem.intType));
+      setValue(node, nonConstant(typeSystem.uint32Type));
     }
   }