MIPS: Fix uint32-to-smi conversion in Lithium.

Port r17441 (f1968f4)

BUG=chromium:309623
TEST=mjsunit/regress/regress-crbug-309623
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/49783010

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17451 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/lithium-codegen-mips.cc

@@ -4584,9 +4584,7 @@ void LCodeGen::DoInteger32ToDouble(LInteger32ToDouble* instr) {
 
 void LCodeGen::DoInteger32ToSmi(LInteger32ToSmi* instr) {
   LOperand* input = instr->value();
-  ASSERT(input->IsRegister());
   LOperand* output = instr->result();
-  ASSERT(output->IsRegister());
   Register scratch = scratch0();
 
   __ SmiTagCheckOverflow(ToRegister(output), ToRegister(input), scratch);
@@ -4607,6 +4605,19 @@ void LCodeGen::DoUint32ToDouble(LUint32ToDouble* instr) {
 }
 
 
+void LCodeGen::DoUint32ToSmi(LUint32ToSmi* instr) {
+  LOperand* input = instr->value();
+  LOperand* output = instr->result();
+  if (!instr->hydrogen()->value()->HasRange() ||
+      !instr->hydrogen()->value()->range()->IsInSmiRange()) {
+    Register scratch = scratch0();
+    __ And(scratch, ToRegister(input), Operand(0xc0000000));
+    DeoptimizeIf(ne, instr->environment(), scratch, Operand(zero_reg));
+  }
+  __ SmiTag(ToRegister(output), ToRegister(input));
+}
+
+
 void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
   class DeferredNumberTagI V8_FINAL : public LDeferredCode {
    public:

src/mips/lithium-mips.cc

@@ -1934,8 +1934,9 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
     } else if (to.IsSmi()) {
       HValue* val = instr->value();
       LOperand* value = UseRegister(val);
-      LInstruction* result =
-          DefineSameAsFirst(new(zone()) LInteger32ToSmi(value));
+      LInstruction* result = val->CheckFlag(HInstruction::kUint32)
+          ? DefineSameAsFirst(new(zone()) LUint32ToSmi(value))
+          : DefineSameAsFirst(new(zone()) LInteger32ToSmi(value));
       if (val->HasRange() && val->range()->IsInSmiRange()) {
         return result;
       }

src/mips/lithium-mips.h

@@ -182,6 +182,7 @@ class LCodeGen;
   V(Typeof)                                     \
   V(TypeofIsAndBranch)                          \
   V(Uint32ToDouble)                             \
+  V(Uint32ToSmi)                                \
   V(UnknownOSRValue)                            \
   V(ValueOf)                                    \
   V(WrapReceiver)
@@ -2052,6 +2053,19 @@ class LUint32ToDouble V8_FINAL : public LTemplateInstruction<1, 1, 0> {
 };
 
 
+class LUint32ToSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
+ public:
+  explicit LUint32ToSmi(LOperand* value) {
+    inputs_[0] = value;
+  }
+
+  LOperand* value() { return inputs_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(Uint32ToSmi, "uint32-to-smi")
+  DECLARE_HYDROGEN_ACCESSOR(Change)
+};
+
+
 class LNumberTagI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LNumberTagI(LOperand* value) {