Comparison in effect context lazy deopt fix.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index d3d7b5837a0c5e3d9a09ba4a58ce9486773818e8..0af75ce4ae60199623b75b5bcbbe441b4ea9b8d8 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -4375,7 +4375,7 @@ void HOptimizedGraphBuilder::VisitSwitchStatement(SwitchStatement* stmt) {
     HControlInstruction* compare = BuildCompareInstruction(
         Token::EQ_STRICT, tag_value, label_value, tag_type, label_type,
         combined_type, stmt->tag()->position(), clause->label()->position(),
-        clause->id());
+        PUSH_BEFORE_SIMULATE, clause->id());
 
     HBasicBlock* next_test_block = graph()->CreateBasicBlock();
     HBasicBlock* body_block = graph()->CreateBasicBlock();
@@ -9527,9 +9527,13 @@ void HOptimizedGraphBuilder::VisitCompareOperation(CompareOperation* expr) {
     return ast_context()->ReturnInstruction(result, expr->id());
   }
 
+  PushBeforeSimulateBehavior push_behavior =
+    ast_context()->IsEffect() ? NO_PUSH_BEFORE_SIMULATE
+                              : PUSH_BEFORE_SIMULATE;
   HControlInstruction* compare = BuildCompareInstruction(
       op, left, right, left_type, right_type, combined_type,
-      expr->left()->position(), expr->right()->position(), expr->id());
+      expr->left()->position(), expr->right()->position(),
+      push_behavior, expr->id());
   if (compare == NULL) return;  // Bailed out.
   return ast_context()->ReturnControl(compare, expr->id());
 }
@@ -9544,6 +9548,7 @@ HControlInstruction* HOptimizedGraphBuilder::BuildCompareInstruction(
     Type* combined_type,
     int left_position,
     int right_position,
+    PushBeforeSimulateBehavior push_sim_result,
     BailoutId bailout_id) {
   // Cases handled below depend on collected type feedback. They should
   // soft deoptimize when there is no type feedback.
@@ -9608,9 +9613,14 @@ HControlInstruction* HOptimizedGraphBuilder::BuildCompareInstruction(
       result->set_observed_input_representation(1, left_rep);
       result->set_observed_input_representation(2, right_rep);
       if (result->HasObservableSideEffects()) {
-        Push(result);
-        AddSimulate(bailout_id, REMOVABLE_SIMULATE);
-        Drop(1);
+        if (push_sim_result == NO_PUSH_BEFORE_SIMULATE) {

[Jakob Kummerow, 2014/02/13 15:55:32]

nit: I'd find it slightly more readable to swap the condition; then you can also
drop the ASSERT (it's clear enough what's going on):

if (push_sim_result == PUSH_BEFORE_SIMULATE) {
  Push(result);
  AddSimulate(bailout_id, REMOVABLE_SIMULATE);
  Drop(1);
} else {
  AddSimulate(bailout_id, REMOVABLE_SIMULATE);
}

+          AddSimulate(bailout_id, REMOVABLE_SIMULATE);
+        } else {
+          ASSERT(push_sim_result == PUSH_BEFORE_SIMULATE);
+          Push(result);
+          AddSimulate(bailout_id, REMOVABLE_SIMULATE);
+          Drop(1);
+        }
       }
       // TODO(jkummerow): Can we make this more efficient?
       HBranch* branch = New<HBranch>(result);