Optimize DateTime properties

pkg/compiler/lib/src/ssa/invoke_dynamic_specializers.dart

Index: pkg/compiler/lib/src/ssa/invoke_dynamic_specializers.dart
diff --git a/pkg/compiler/lib/src/ssa/invoke_dynamic_specializers.dart b/pkg/compiler/lib/src/ssa/invoke_dynamic_specializers.dart
index 7f5ff1d584fcc09a01da15778c627a2e97d30d11..c8cfebc91b45293457c033c1b59d729945acb2be 100644
--- a/pkg/compiler/lib/src/ssa/invoke_dynamic_specializers.dart
+++ b/pkg/compiler/lib/src/ssa/invoke_dynamic_specializers.dart
@@ -223,11 +223,16 @@ abstract class BinaryArithmeticSpecializer extends InvokeDynamicSpecializer {
   bool inputsArePositiveIntegers(HInstruction instruction, Compiler compiler) {
     HInstruction left = instruction.inputs[1];
     HInstruction right = instruction.inputs[2];
-    JavaScriptBackend backend = compiler.backend;
     return left.isPositiveIntegerOrNull(compiler)
         && right.isPositiveIntegerOrNull(compiler);
   }
 
+  bool inputsAreUInt31(HInstruction instruction, Compiler compiler) {
+    HInstruction left = instruction.inputs[1];
+    HInstruction right = instruction.inputs[2];
+    return left.isUInt31(compiler) && right.isUInt31(compiler);
+  }
+
   HInstruction newBuiltinVariant(HInvokeDynamic instruction, Compiler compiler);
 
   Selector renameToOptimizedSelector(String name,
@@ -249,6 +254,10 @@ class AddSpecializer extends BinaryArithmeticSpecializer {
 
   TypeMask computeTypeFromInputTypes(HInvokeDynamic instruction,
                                      Compiler compiler) {
+    if (inputsAreUInt31(instruction, compiler)) {
+      JavaScriptBackend backend = compiler.backend;
+      return backend.uint32Type;
+    }
     if (inputsArePositiveIntegers(instruction, compiler)) {
       JavaScriptBackend backend = compiler.backend;
       return backend.positiveIntType;
@@ -313,6 +322,7 @@ class ModuloSpecializer extends BinaryArithmeticSpecializer {
   HInstruction newBuiltinVariant(HInvokeDynamic instruction,
                                  Compiler compiler) {
     // Modulo cannot be mapped to the native operator (different semantics).
+    // TODO(sra): For non-negative values we can use JavaScript's %.
     return null;
   }
 }
@@ -365,8 +375,11 @@ class TruncatingDivideSpecializer extends BinaryArithmeticSpecializer {
 
   TypeMask computeTypeFromInputTypes(HInvokeDynamic instruction,
                                      Compiler compiler) {
+    JavaScriptBackend backend = compiler.backend;
+    if (hasUint31Result(instruction, compiler)) {
+      return backend.uint31Type;
+    }
     if (inputsArePositiveIntegers(instruction, compiler)) {
-      JavaScriptBackend backend = compiler.backend;
       return backend.positiveIntType;
     }
     return super.computeTypeFromInputTypes(instruction, compiler);
@@ -380,13 +393,35 @@ class TruncatingDivideSpecializer extends BinaryArithmeticSpecializer {
     return count != 0;
   }
 
+  bool isTwoOrGreater(HInstruction instruction, Compiler compiler) {
+    if (!instruction.isConstantInteger()) return false;
+    HConstant rightConstant = instruction;
+    IntConstantValue intConstant = rightConstant.constant;
+    int count = intConstant.primitiveValue;
+    return count >= 2;
+  }
+
+  bool hasUint31Result(HInstruction instruction, Compiler compiler) {
+    HInstruction left = instruction.inputs[1];
+    HInstruction right = instruction.inputs[2];
+    if (right.isPositiveInteger(compiler)) {
+      if (left.isUInt31(compiler) && isNotZero(right, compiler)) {
+        return true;
+      }
+      if (left.isUInt32(compiler) && isTwoOrGreater(right, compiler)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   HInstruction tryConvertToBuiltin(HInvokeDynamic instruction,
                                    Compiler compiler) {
     HInstruction left = instruction.inputs[1];
     HInstruction right = instruction.inputs[2];
     if (isBuiltin(instruction, compiler)) {
       if (right.isPositiveInteger(compiler) && isNotZero(right, compiler)) {
-        if (left.isUInt31(compiler)) {
+        if (hasUint31Result(instruction, compiler)) {
           return newBuiltinVariant(instruction, compiler);
         }
         // We can call _tdivFast because the rhs is a 32bit integer