Improve smi shift operations and avoid repeated deoptimizations.

runtime/vm/flow_graph_optimizer.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
@@ skipping 663 matching lines @@
 
 bool FlowGraphOptimizer::TryReplaceWithBinaryOp(InstanceCallInstr* call,
                                                 Token::Kind op_kind) {
   intptr_t operands_type = kIllegalCid;
   ASSERT(call->HasICData());
   const ICData& ic_data = *call->ic_data();
   switch (op_kind) {
     case Token::kADD:
     case Token::kSUB:
       if (HasOnlyTwoSmis(ic_data)) {
-        operands_type = kSmiCid;
+        // Don't generate smi code if the IC data is marked because
+        // of an overflow.
+        operands_type = (ic_data.deopt_reason() == kDeoptBinarySmiOp)
+            ? kMintCid
+            : kSmiCid;
       } else if (HasTwoMintOrSmi(ic_data) &&
                  FlowGraphCompiler::SupportsUnboxedMints()) {
+        // Don't generate mint code if the IC data is marked because of an
+        // overflow.
+        if (ic_data.deopt_reason() == kDeoptBinaryMintOp) return false;
         operands_type = kMintCid;
       } else if (ShouldSpecializeForDouble(ic_data)) {
         operands_type = kDoubleCid;
       } else {
         return false;
       }
       break;
     case Token::kMUL:
       if (HasOnlyTwoSmis(ic_data)) {
+        // Don't generate smi code if the IC data is marked because of an
+        // overflow.
+        // TODO(fschneider): Add unboxed mint multiplication.
+        if (ic_data.deopt_reason() == kDeoptBinarySmiOp) return false;
         operands_type = kSmiCid;
       } else if (ShouldSpecializeForDouble(ic_data)) {
         operands_type = kDoubleCid;
       } else {
         return false;
       }
       break;
     case Token::kDIV:
       if (ShouldSpecializeForDouble(ic_data)) {
         operands_type = kDoubleCid;
       } else {
         return false;
       }
       break;
     case Token::kMOD:
       if (HasOnlyTwoSmis(ic_data)) {
         operands_type = kSmiCid;
       } else {
         return false;
       }
       break;
     case Token::kBIT_AND:
     case Token::kBIT_OR:
     case Token::kBIT_XOR:
       if (HasOnlyTwoSmis(ic_data)) {
         operands_type = kSmiCid;
-      } else if (HasTwoMintOrSmi(ic_data) &&
-                 FlowGraphCompiler::SupportsUnboxedMints()) {
+      } else if (HasTwoMintOrSmi(ic_data)) {
         operands_type = kMintCid;
       } else {
         return false;
       }
       break;
     case Token::kSHR:
     case Token::kSHL:
       if (HasOnlyTwoSmis(ic_data)) {
-        operands_type = kSmiCid;
-      } else if (FlowGraphCompiler::SupportsUnboxedMints() &&
-                 HasTwoMintOrSmi(ic_data) &&
+        // Left shift may overflow from smi into mint or big ints.
+        // Don't generate smi code if the IC data is marked because
+        // of an overflow.
+        if (ic_data.deopt_reason() == kDeoptShiftMintOp) return false;
+        operands_type = (ic_data.deopt_reason() == kDeoptBinarySmiOp)
+            ? kMintCid
+            : kSmiCid;
+      } else if (HasTwoMintOrSmi(ic_data) &&
                  HasOnlyOneSmi(ICData::Handle(
                      ic_data.AsUnaryClassChecksForArgNr(1)))) {
+        // Don't generate mint code if the IC data is marked because of an
+        // overflow.
+        if (ic_data.deopt_reason() == kDeoptShiftMintOp) return false;
         // Check for smi/mint << smi or smi/mint >> smi.
         operands_type = kMintCid;
       } else {
         return false;
       }
       break;
     case Token::kTRUNCDIV:
       if (HasOnlyTwoSmis(ic_data)) {
+        if (ic_data.deopt_reason() == kDeoptBinarySmiOp) return false;
         operands_type = kSmiCid;
       } else {
         return false;
       }
       break;
     default:
       UNREACHABLE();
   };
 
   ASSERT(call->ArgumentCount() == 2);
   if (operands_type == kDoubleCid) {
     Value* left = call->ArgumentAt(0)->value();
     Value* right = call->ArgumentAt(1)->value();
 
     // Check that either left or right are not a smi.  Result or a
     // binary operation with two smis is a smi not a double.
     InsertBefore(call,
                  new CheckEitherNonSmiInstr(left->Copy(),
                                             right->Copy(),
                                             call),
                  call->env(),
                  Definition::kEffect);
 
     BinaryDoubleOpInstr* double_bin_op =
         new BinaryDoubleOpInstr(op_kind, left->Copy(), right->Copy(), call);
     call->ReplaceWith(double_bin_op, current_iterator());
     RemovePushArguments(call);
   } else if (operands_type == kMintCid) {
+    if (!FlowGraphCompiler::SupportsUnboxedMints()) return false;
     Value* left = call->ArgumentAt(0)->value();
     Value* right = call->ArgumentAt(1)->value();
     if ((op_kind == Token::kSHR) || (op_kind == Token::kSHL)) {
       ShiftMintOpInstr* shift_op =
           new ShiftMintOpInstr(op_kind, left, right, call);
       call->ReplaceWith(shift_op, current_iterator());
     } else {
       BinaryMintOpInstr* bin_op =
           new BinaryMintOpInstr(op_kind, left, right, call);
       call->ReplaceWith(bin_op, current_iterator());
@@ skipping 2930 matching lines @@
 
   if (FLAG_trace_constant_propagation) {
     OS::Print("\n==== After constant propagation ====\n");
     FlowGraphPrinter printer(*graph_);
     printer.PrintBlocks();
   }
 }
 
 
 }  // namespace dart