MIPS: Add Smi support to Shl

src/mips/lithium-mips.cc

Index: src/mips/lithium-mips.cc
diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index b03cea44cbfa5dfc64d0e93fcdb074bb5cc0b9a8..0449c2afa909a4c9ace6483c43746caaa2a2dd56 100644
--- a/src/mips/lithium-mips.cc
+++ b/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

[Paul Lind, 2013/07/26 22:58:58]

nit: this comment should have the word 'only' removed, since you just added
another case where shift can deoptimize.

[palfia, 2013/07/26 23:55:02]

Done.

   // 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);