VM: Remove PushTempInstr, simplify SSA renaming.

runtime/vm/flow_graph_builder.cc

Index: runtime/vm/flow_graph_builder.cc
diff --git a/runtime/vm/flow_graph_builder.cc b/runtime/vm/flow_graph_builder.cc
index 0a78c7b0e40c302b8e266a57144d2651899b7fe9..b9685854b9f24866daf0a5b243c1575c35c5d6d2 100644
--- a/runtime/vm/flow_graph_builder.cc
+++ b/runtime/vm/flow_graph_builder.cc
@@ -2247,9 +2247,6 @@ intptr_t EffectGraphVisitor::GetCurrentTempLocalIndex() const {
 
 LocalVariable* EffectGraphVisitor::EnterTempLocalScope(
     Value* value, TokenPosition token_pos) {
-  Do(new(Z) PushTempInstr(value));
-  owner()->AllocateTemp();
-
   ASSERT(value->definition()->temp_index() == (owner()->temp_count() - 1));
   intptr_t index = GetCurrentTempLocalIndex();
   char name[64];
@@ -2278,12 +2275,9 @@ void EffectGraphVisitor::BuildLetTempExpressions(LetNode* node) {
     ValueGraphVisitor for_value(owner());
     node->InitializerAt(i)->Visit(&for_value);
     Append(for_value);
-    Value* temp_val = for_value.value();
     ASSERT(!node->TempAt(i)->HasIndex() ||
            (node->TempAt(i)->index() == GetCurrentTempLocalIndex()));
     node->TempAt(i)->set_index(GetCurrentTempLocalIndex());
-    Do(new(Z) PushTempInstr(temp_val));
-    owner()->AllocateTemp();
   }
 }