VM: Fix bug in type propagation at conditionals.

runtime/vm/flow_graph_type_propagator.cc

 // Copyright (c) 2013, 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_type_propagator.h"
 
 #include "vm/cha.h"
 #include "vm/bit_vector.h"
 #include "vm/il_printer.h"
 #include "vm/regexp_assembler.h"
@@ skipping 131 matching lines @@
   GotoInstr* goto_instr = block->last_instruction()->AsGoto();
   if (goto_instr != NULL) {
     JoinEntryInstr* join = goto_instr->successor();
     intptr_t pred_index = join->IndexOfPredecessor(block);
     ASSERT(pred_index >= 0);
     for (PhiIterator it(join); !it.Done(); it.Advance()) {
       VisitValue(it.Current()->InputAt(pred_index));
     }
   }
 
-  HandleBranchOnStrictCompare(block);
-
   for (intptr_t i = 0; i < block->dominated_blocks().length(); ++i) {
     PropagateRecursive(block->dominated_blocks()[i]);
   }
 
   RollbackTo(rollback_point);
 }
 
 
-void FlowGraphTypePropagator::HandleBranchOnStrictCompare(
-    BlockEntryInstr* block) {
-  BranchInstr* branch = block->last_instruction()->AsBranch();
-  if (branch == NULL) {
-    return;
-  }
-
-  StrictCompareInstr* compare = branch->comparison()->AsStrictCompare();
-  if ((compare == NULL) || !compare->right()->BindsToConstant()) {
-    return;
-  }
-
-  const intptr_t rollback_point = rollback_.length();
-
-  Definition* defn = compare->left()->definition();
-  const Object& right = compare->right()->BoundConstant();
-  intptr_t cid = right.GetClassId();
-
-  if (defn->IsLoadClassId() && right.IsSmi()) {
-    defn = defn->AsLoadClassId()->object()->definition();
-    cid = Smi::Cast(right).Value();
-  }
-
-  if (!CheckClassInstr::IsImmutableClassId(cid)) {
-    if ((cid == kOneByteStringCid) || (cid == kTwoByteStringCid)) {
-      SetTypeOf(defn, ZoneCompileType::Wrap(CompileType::String()));
-      PropagateRecursive((compare->kind() == Token::kEQ_STRICT) ?
-          branch->true_successor() : branch->false_successor());
-      RollbackTo(rollback_point);
-    }
-    return;
-  }
-
-  if (compare->kind() == Token::kEQ_STRICT) {
-    if (cid == kNullCid) {
-      branch->set_constrained_type(MarkNonNullable(defn));
-      PropagateRecursive(branch->false_successor());
-    }
-
-    SetCid(defn, cid);
-    PropagateRecursive(branch->true_successor());
-  } else if (compare->kind() == Token::kNE_STRICT) {
-    if (cid == kNullCid) {
-      branch->set_constrained_type(MarkNonNullable(defn));
-      PropagateRecursive(branch->true_successor());
-    }
-
-    SetCid(defn, cid);
-    PropagateRecursive(branch->false_successor());
-  }
-
-  RollbackTo(rollback_point);
-}
-
-
 void FlowGraphTypePropagator::RollbackTo(intptr_t rollback_point) {
   for (intptr_t i = rollback_.length() - 1; i >= rollback_point; i--) {
     types_[rollback_[i].index()] = rollback_[i].type();
   }
   rollback_.TruncateTo(rollback_point);
 }
 
 
 CompileType* FlowGraphTypePropagator::TypeOf(Definition* def) {
   const intptr_t index = def->ssa_temp_index();
@@ skipping 1220 matching lines @@
 CompileType MergedMathInstr::ComputeType() const {
   return CompileType::Dynamic();
 }
 
 
 CompileType ExtractNthOutputInstr::ComputeType() const {
   return CompileType::FromCid(definition_cid_);
 }
 
 }  // namespace dart