Merge bleeding_edge r17376:17693.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 6da6774aa8e87302bdd2a03a9f4f31f88d8216e7..39d59582beec3d1ba57cad734dc5713e5bdda976 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -1255,8 +1255,15 @@ static bool IsIdentityOperation(HValue* arg1, HValue* arg2, int32_t identity) {
 
 
 HValue* HAdd::Canonicalize() {
-  if (IsIdentityOperation(left(), right(), 0)) return left();
-  if (IsIdentityOperation(right(), left(), 0)) return right();
+  // Adding 0 is an identity operation except in case of -0: -0 + 0 = +0
+  if (IsIdentityOperation(left(), right(), 0) &&
+      !left()->representation().IsDouble()) {  // Left could be -0.
+    return left();
+  }
+  if (IsIdentityOperation(right(), left(), 0) &&
+      !left()->representation().IsDouble()) {  // Right could be -0.
+    return right();
+  }
   return this;
 }
 
@@ -2849,8 +2856,17 @@ Range* HShl::InferRange(Zone* zone) {
 
 
 Range* HLoadNamedField::InferRange(Zone* zone) {
-  if (access().representation().IsByte()) {
-    return new(zone) Range(0, 255);
+  if (access().representation().IsInteger8()) {
+    return new(zone) Range(kMinInt8, kMaxInt8);
+  }
+  if (access().representation().IsUInteger8()) {
+    return new(zone) Range(kMinUInt8, kMaxUInt8);
+  }
+  if (access().representation().IsInteger16()) {
+    return new(zone) Range(kMinInt16, kMaxInt16);
+  }
+  if (access().representation().IsUInteger16()) {
+    return new(zone) Range(kMinUInt16, kMaxUInt16);
   }
   if (access().IsStringLength()) {
     return new(zone) Range(0, String::kMaxLength);
@@ -2861,16 +2877,15 @@ Range* HLoadNamedField::InferRange(Zone* zone) {
 
 Range* HLoadKeyed::InferRange(Zone* zone) {
   switch (elements_kind()) {
-    case EXTERNAL_PIXEL_ELEMENTS:
-      return new(zone) Range(0, 255);
     case EXTERNAL_BYTE_ELEMENTS:
-      return new(zone) Range(-128, 127);
+      return new(zone) Range(kMinInt8, kMaxInt8);
     case EXTERNAL_UNSIGNED_BYTE_ELEMENTS:
-      return new(zone) Range(0, 255);
+    case EXTERNAL_PIXEL_ELEMENTS:
+      return new(zone) Range(kMinUInt8, kMaxUInt8);
     case EXTERNAL_SHORT_ELEMENTS:
-      return new(zone) Range(-32768, 32767);
+      return new(zone) Range(kMinInt16, kMaxInt16);
     case EXTERNAL_UNSIGNED_SHORT_ELEMENTS:
-      return new(zone) Range(0, 65535);
+      return new(zone) Range(kMinUInt16, kMaxUInt16);
     default:
       return HValue::InferRange(zone);
   }
@@ -2929,6 +2944,24 @@ void HCompareHoleAndBranch::InferRepresentation(
 }
 
 
+bool HCompareMinusZeroAndBranch::KnownSuccessorBlock(HBasicBlock** block) {
+  if (value()->representation().IsSmiOrInteger32()) {
+    // A Smi or Integer32 cannot contain minus zero.
+    *block = SecondSuccessor();
+    return true;
+  }
+  *block = NULL;
+  return false;
+}
+
+
+void HCompareMinusZeroAndBranch::InferRepresentation(
+    HInferRepresentationPhase* h_infer) {
+  ChangeRepresentation(value()->representation());
+}
+
+
+
 void HGoto::PrintDataTo(StringStream* stream) {
   stream->Add("B%d", SuccessorAt(0)->block_id());
 }
@@ -3984,6 +4017,26 @@ HInstruction* HShr::New(
 }
 
 
+HInstruction* HSeqStringGetChar::New(Zone* zone,
+                                     HValue* context,
+                                     String::Encoding encoding,
+                                     HValue* string,
+                                     HValue* index) {
+  if (FLAG_fold_constants && string->IsConstant() && index->IsConstant()) {
+    HConstant* c_string = HConstant::cast(string);
+    HConstant* c_index = HConstant::cast(index);
+    if (c_string->HasStringValue() && c_index->HasInteger32Value()) {
+      Handle<String> s = c_string->StringValue();
+      int32_t i = c_index->Integer32Value();
+      ASSERT_LE(0, i);
+      ASSERT_LT(i, s->length());
+      return H_CONSTANT_INT(s->Get(i));
+    }
+  }
+  return new(zone) HSeqStringGetChar(encoding, string, index);
+}
+
+
 #undef H_CONSTANT_INT
 #undef H_CONSTANT_DOUBLE