[hydrogen] don't bailout assignments to consts

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index d3ed88b529018bd617400448617576e3701b3ff9..e09aa42dd099be7d795b405e2aa60727a0f66a12 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -2171,6 +2171,15 @@ void LCodeGen::DoLoadContextSlot(LLoadContextSlot* instr) {
 void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
   Register context = ToRegister(instr->context());
   Register value = ToRegister(instr->value());
+
+  Label skip_assignment;
+
+  if (instr->RequiresHoleCheck()) {
+    __ cmp(ContextOperand(context, instr->slot_index()),
+           factory()->the_hole_value());
+    __ j(not_equal, &skip_assignment, Label::kNear);
+  }
+
   __ mov(ContextOperand(context, instr->slot_index()), value);
   if (instr->hydrogen()->NeedsWriteBarrier()) {
     HType type = instr->hydrogen()->value()->type();
@@ -2186,6 +2195,8 @@ void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
                               EMIT_REMEMBERED_SET,
                               check_needed);
   }
+
+  __ bind(&skip_assignment);
 }