MIPS: Tag length of FixedArrayBase and smi-array[x] as smi representation

Port r14778 (c7fdf61b)

BUG=

Review URL: https://codereview.chromium.org/15927005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14786 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/lithium-codegen-mips.cc

@@ -4958,6 +4958,13 @@ void LCodeGen::DoDoubleToSmi(LDoubleToSmi* instr) {
 }
 
 
+void LCodeGen::DoCheckSmiAndReturn(LCheckSmiAndReturn* instr) {
+  LOperand* input = instr->value();
+  __ And(at, ToRegister(input), Operand(kSmiTagMask));
+  DeoptimizeIf(ne, instr->environment(), at, Operand(zero_reg));
+}
+
+
 void LCodeGen::DoCheckSmi(LCheckSmi* instr) {
   LOperand* input = instr->value();
   __ And(at, ToRegister(input), Operand(kSmiTagMask));

src/mips/lithium-mips.cc

@@ -1763,6 +1763,12 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
   if (from.IsSmi()) {
     if (to.IsTagged()) {
       LOperand* value = UseRegister(instr->value());
+      // For now, always deopt on hole.
+      if (instr->value()->IsLoadKeyed() &&
+          HLoadKeyed::cast(instr->value())->UsesMustHandleHole()) {
+        return AssignEnvironment(
+            DefineSameAsFirst(new(zone()) LCheckSmiAndReturn(value)));
+      }
       return DefineSameAsFirst(new(zone()) LDummyUse(value));
     }
     from = Representation::Tagged();
@@ -1775,9 +1781,9 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
       return AssignEnvironment(DefineAsRegister(res));
     } else if (to.IsSmi()) {
       HValue* val = instr->value();
-      LOperand* value = UseRegisterAtStart(val);
+      LOperand* value = UseRegister(val);
       return AssignEnvironment(
-          DefineSameAsFirst(new(zone()) LCheckSmi(value)));
+          DefineSameAsFirst(new(zone()) LCheckSmiAndReturn(value)));
     } else {
       ASSERT(to.IsInteger32());
       LOperand* value = NULL;

src/mips/lithium-mips.h

@@ -76,6 +76,7 @@ class LCodeGen;
   V(CheckNonSmi)                                \
   V(CheckPrototypeMaps)                         \
   V(CheckSmi)                                   \
+  V(CheckSmiAndReturn)                          \
   V(ClampDToUint8)                              \
   V(ClampIToUint8)                              \
   V(ClampTToUint8)                              \
@@ -2328,7 +2329,7 @@ class LCheckPrototypeMaps: public LTemplateInstruction<0, 0, 2> {
 };
 
 
-class LCheckSmi: public LTemplateInstruction<1, 1, 0> {
+class LCheckSmi: public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckSmi(LOperand* value) {
     inputs_[0] = value;
@@ -2340,6 +2341,18 @@ class LCheckSmi: public LTemplateInstruction<1, 1, 0> {
 };
 
 
+class LCheckSmiAndReturn: public LTemplateInstruction<1, 1, 0> {
+ public:
+  explicit LCheckSmiAndReturn(LOperand* value) {
+    inputs_[0] = value;
+  }
+
+  LOperand* value() { return inputs_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(CheckSmiAndReturn, "check-smi-and-return")
+};
+
+
 class LCheckNonSmi: public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckNonSmi(LOperand* value) {