Support for multiple register values

runtime/vm/flow_graph.cc

Index: runtime/vm/flow_graph.cc
diff --git a/runtime/vm/flow_graph.cc b/runtime/vm/flow_graph.cc
index 98a774ba959d34490aafbb61b4990beaace9bcbb..bd24cf64e936e18d55d3f3816f4ae1189cf52322 100644
--- a/runtime/vm/flow_graph.cc
+++ b/runtime/vm/flow_graph.cc
@@ -115,7 +115,11 @@ void FlowGraph::InsertAfter(Instruction* prev,
                             Definition::UseKind use_kind) {
   if (use_kind == Definition::kValue) {
     ASSERT(instr->IsDefinition());
-    instr->AsDefinition()->set_ssa_temp_index(alloc_ssa_temp_index());
+    Definition* defn = instr->AsDefinition();
+    defn->set_ssa_temp_index(alloc_ssa_temp_index());
+    if (defn->RequiresTwoSSATempIndexes()) {
+      defn->set_ssa_temp_index2(alloc_ssa_temp_index());

[Vyacheslav Egorov (Google), 2014/04/03 18:10:09]

I am not sure I like the naming here.

[Cutch, 2014/04/03 18:35:07]

I've renamed it to pair_ssa_index. I don't really like either name.

virtual bool RequiresPairSSAIndex() const;
virtual intptr_t pair_ssa_index() const;
virtual void set_pair_ssa_index(intptr_t idx);

+    }
   }
   instr->InsertAfter(prev);
   ASSERT(instr->env() == NULL);
@@ -129,7 +133,11 @@ Instruction* FlowGraph::AppendTo(Instruction* prev,
                                  Definition::UseKind use_kind) {
   if (use_kind == Definition::kValue) {
     ASSERT(instr->IsDefinition());
-    instr->AsDefinition()->set_ssa_temp_index(alloc_ssa_temp_index());
+    Definition* defn = instr->AsDefinition();
+    defn->set_ssa_temp_index(alloc_ssa_temp_index());
+    if (defn->RequiresTwoSSATempIndexes()) {

[Vyacheslav Egorov (Google), 2014/04/03 18:10:09]

The code is duplicated in multiple places. I wonder if we can just shift it into
a separate function.

AssignSSATempIndex(instr);

[Cutch, 2014/04/03 18:35:07]

Done. Added the following to FlowGraph:

void AssignSSAIndexes(Definition* def);

+      defn->set_ssa_temp_index2(alloc_ssa_temp_index());
+    }
   }
   ASSERT(instr->env() == NULL);
   if (env != NULL) env->DeepCopyTo(instr);
@@ -717,6 +725,9 @@ void FlowGraph::Rename(GrowableArray<PhiInstr*>* live_phis,
     for (intptr_t i = 0; i < parameter_count(); ++i) {
       Definition* defn = (*inlining_parameters)[i];
       defn->set_ssa_temp_index(alloc_ssa_temp_index());  // New SSA temp.
+      if (defn->RequiresTwoSSATempIndexes()) {
+        defn->set_ssa_temp_index2(alloc_ssa_temp_index());
+      }
       AddToInitialDefinitions(defn);
       env.Add(defn);
     }
@@ -927,6 +938,9 @@ void FlowGraph::RenameRecursive(BlockEntryInstr* block_entry,
         if (definition->is_used()) {
           // Assign fresh SSA temporary and update expression stack.
           definition->set_ssa_temp_index(alloc_ssa_temp_index());
+          if (definition->RequiresTwoSSATempIndexes()) {
+            definition->set_ssa_temp_index2(alloc_ssa_temp_index());
+          }
           env->Add(definition);
         }
       }