Fix smi-based math floor.

BUG=chromium:270268
R=svenpanne@chromium.org

Review URL: https://chromiumcodereview.appspot.com/22623007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16128 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen-instructions.cc

@@ -1285,6 +1285,15 @@ static HValue* SimplifiedDividendForMathFloorOfDiv(HValue* dividend) {
 
 
 HValue* HUnaryMathOperation::Canonicalize() {
+  if (op() == kMathRound) {
+    HValue* val = value();
+    if (val->IsChange()) val = HChange::cast(val)->value();
+
+    // If the input is integer32 then we replace the round instruction
+    // with its input.
+    if (val->representation().IsSmiOrInteger32()) return val;
+  }
+
   if (op() == kMathFloor) {
     HValue* val = value();
     if (val->IsChange()) val = HChange::cast(val)->value();
@@ -3313,7 +3322,11 @@ Representation HUnaryMathOperation::RepresentationFromInputs() {
   // If any of the actual input representation is more general than what we
   // have so far but not Tagged, use that representation instead.
   Representation input_rep = value()->representation();
-  if (!input_rep.IsTagged()) rep = rep.generalize(input_rep);
+  if (!input_rep.IsTagged()) {
+    rep = rep.generalize(input_rep);
+  } else if (flexible_int()) {
+    rep = Representation::Integer32();
+  }
   return rep;
 }
 

src/hydrogen-instructions.h

@@ -2430,6 +2430,21 @@ class HUnaryMathOperation: public HTemplateInstruction<2> {
     }
   }
 
+  virtual void UpdateRepresentation(Representation new_rep,
+                                    HInferRepresentationPhase* h_infer,
+                                    const char* reason) {
+    if (flexible_int() && !new_rep.IsSmi()) {
+      new_rep = Representation::Integer32();
+    }
+    HValue::UpdateRepresentation(new_rep, h_infer, reason);
+  }
+
+  virtual void RepresentationChanged(Representation new_rep) {
+    if (flexible_int() && new_rep.IsInteger32()) {
+      ClearFlag(kFlexibleRepresentation);
+    }
+  }
+
   virtual Range* InferRange(Zone* zone);
 
   virtual HValue* Canonicalize();
@@ -2447,6 +2462,10 @@ class HUnaryMathOperation: public HTemplateInstruction<2> {
   }
 
  private:
+  bool flexible_int() {
+    return op_ == kMathFloor || op_ == kMathRound;
+  }
+
   HUnaryMathOperation(HValue* context, HValue* value, BuiltinFunctionId op)
       : HTemplateInstruction<2>(HType::TaggedNumber()), op_(op) {
     SetOperandAt(0, context);
@@ -2454,8 +2473,8 @@ class HUnaryMathOperation: public HTemplateInstruction<2> {
     switch (op) {
       case kMathFloor:
       case kMathRound:
-        // TODO(verwaest): Set representation to flexible int starting as smi.
-        set_representation(Representation::Integer32());
+        set_representation(Representation::Smi());
+        SetFlag(kFlexibleRepresentation);
         break;
       case kMathAbs:
         // Not setting representation here: it is None intentionally.

src/hydrogen.cc

@@ -8041,10 +8041,6 @@ void HOptimizedGraphBuilder::VisitCompareOperation(CompareOperation* expr) {
       result->set_position(expr->position());
       return ast_context()->ReturnInstruction(result, expr->id());
     } else {
-      // TODO(verwaest): Remove once Representation::FromType properly
-      // returns Smi when the IC measures Smi.
-      if (left_type->Is(Type::Smi())) left_rep = Representation::Smi();
-      if (right_type->Is(Type::Smi())) right_rep = Representation::Smi();
       HCompareNumericAndBranch* result =
           new(zone()) HCompareNumericAndBranch(left, right, op);
       result->set_observed_input_representation(left_rep, right_rep);

test/mjsunit/regress/regress-smi-math-floor-round.js

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --allow-natives-syntax
+
+
+function f(o) {
+  return Math.floor(o.x_smi) + 1;
+}
+
+assertEquals(2, f({x_smi:1}));
+assertEquals(2, f({x_smi:1}));
+%OptimizeFunctionOnNextCall(f);
+assertEquals(2, f({x_smi:1}));
+
+function f2(o) {
+  return Math.floor(o.x_tagged) + 1;
+}
+
+var o = {x_tagged:{}};
+o.x_tagged = 1.4;
+assertEquals(2, f2(o));
+assertEquals(2, f2(o));
+%OptimizeFunctionOnNextCall(f2);
+assertEquals(2, f2(o));
+
+function f3(o) {
+  return Math.round(o.x_smi) + 1;
+}
+
+assertEquals(2, f3({x_smi:1}));
+assertEquals(2, f3({x_smi:1}));
+%OptimizeFunctionOnNextCall(f3);
+assertEquals(2, f3({x_smi:1}));
+
+function f4(o) {
+  return Math.round(o.x_tagged) + 1;
+}
+
+assertEquals(2, f4(o));
+assertEquals(2, f4(o));
+%OptimizeFunctionOnNextCall(f4);
+assertEquals(2, f4(o));