Convert ToBooleanStub to a HydrogenStub. Currently just using HBranch, which is still fully impleme…

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index f9b6e817af594436875be9e8e99e08379befc1d6..f359643a81ebead725eeaa191a696b34e2c9a327 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -1899,6 +1899,7 @@ void LCodeGen::DoBranch(LBranch* instr) {
   int true_block = chunk_->LookupDestination(instr->true_block_id());
   int false_block = chunk_->LookupDestination(instr->false_block_id());
 
+  FOR_ASSERT(bool considered_typefeedback = false);
   Representation r = instr->hydrogen()->value()->representation();
   if (r.IsInteger32()) {
     Register reg = ToRegister(instr->value());
@@ -1927,6 +1928,7 @@ void LCodeGen::DoBranch(LBranch* instr) {
       Label* true_label = chunk_->GetAssemblyLabel(true_block);
       Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
+      FOR_ASSERT(considered_typefeedback = true);
       ToBooleanStub::Types expected = instr->hydrogen()->expected_input_types();
       // Avoid deopts in the case where we've never executed this path before.
       if (expected.IsEmpty()) expected = ToBooleanStub::all_types();
@@ -2006,6 +2008,8 @@ void LCodeGen::DoBranch(LBranch* instr) {
       DeoptimizeIf(no_condition, instr->environment());
     }
   }
+  // Make sure not to poison the stub cache.
+  ASSERT(info()->IsStub() ? considered_typefeedback : true);
 }