MIPS: Add Smi support to Shl

Port r15910 (8e65c434)

BUG=

Review URL: https://codereview.chromium.org/20808004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15913 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/lithium-codegen-mips.cc

@@ -1521,6 +1521,7 @@ void LCodeGen::DoShiftI(LShiftI* instr) {
   LOperand* right_op = instr->right();
   Register left = ToRegister(instr->left());
   Register result = ToRegister(instr->result());
+  Register scratch = scratch0();
 
   if (right_op->IsRegister()) {
     // No need to mask the right operand on MIPS, it is built into the variable
@@ -1577,7 +1578,14 @@ void LCodeGen::DoShiftI(LShiftI* instr) {
         break;
       case Token::SHL:
         if (shift_count != 0) {
-          __ sll(result, left, shift_count);
+          if (instr->hydrogen_value()->representation().IsSmi() &&
+              instr->can_deopt()) {
+            __ sll(result, left, shift_count - 1);
+            __ SmiTagCheckOverflow(result, result, scratch);
+            DeoptimizeIf(lt, instr->environment(), scratch, Operand(zero_reg));
+          } else {
+            __ sll(result, left, shift_count);
+          }
         } else {
           __ Move(result, left);
         }

src/mips/lithium-mips.cc

@@ -713,9 +713,9 @@ LInstruction* LChunkBuilder::DoDeoptimize(HDeoptimize* instr) {
 
 LInstruction* LChunkBuilder::DoShift(Token::Value op,
                                      HBitwiseBinaryOperation* instr) {
-  if (instr->representation().IsSmiOrTagged()) {
-    ASSERT(instr->left()->representation().IsSmiOrTagged());
-    ASSERT(instr->right()->representation().IsSmiOrTagged());
+  if (instr->representation().IsTagged()) {
+    ASSERT(instr->left()->representation().IsTagged());
+    ASSERT(instr->right()->representation().IsTagged());
 
     LOperand* left = UseFixed(instr->left(), a1);
     LOperand* right = UseFixed(instr->right(), a0);
@@ -723,25 +723,35 @@ LInstruction* LChunkBuilder::DoShift(Token::Value op,
     return MarkAsCall(DefineFixed(result, v0), instr);
   }
 
-  ASSERT(instr->representation().IsInteger32());
-  ASSERT(instr->left()->representation().IsInteger32());
-  ASSERT(instr->right()->representation().IsInteger32());
+  ASSERT(instr->representation().IsSmiOrInteger32());
+  ASSERT(instr->left()->representation().Equals(instr->representation()));
+  ASSERT(instr->right()->representation().Equals(instr->representation()));
   LOperand* left = UseRegisterAtStart(instr->left());
 
   HValue* right_value = instr->right();
   LOperand* right = NULL;
   int constant_value = 0;
+  bool does_deopt = false;
   if (right_value->IsConstant()) {
     HConstant* constant = HConstant::cast(right_value);
     right = chunk_->DefineConstantOperand(constant);
     constant_value = constant->Integer32Value() & 0x1f;
+    // Left shifts can deoptimize if we shift by > 0 and the result cannot be
+    // truncated to smi.
+    if (instr->representation().IsSmi() && constant_value > 0) {
+      for (HUseIterator it(instr->uses()); !it.Done(); it.Advance()) {
+        if (!it.value()->CheckFlag(HValue::kTruncatingToSmi)) {
+          does_deopt = true;
+          break;
+        }
+      }
+    }
   } else {
     right = UseRegisterAtStart(right_value);
   }
 
-  // Shift operations can only deoptimize if we do a logical shift
+  // Shift operations can deoptimize if we do a logical shift
   // by 0 and the result cannot be truncated to int32.
-  bool does_deopt = false;
   if (op == Token::SHR && constant_value == 0) {
     if (FLAG_opt_safe_uint32_operations) {
       does_deopt = !instr->CheckFlag(HInstruction::kUint32);