Add support for XMM registers in SSA code generation pipeline.

runtime/vm/flow_graph_compiler.cc

Index: runtime/vm/flow_graph_compiler.cc
diff --git a/runtime/vm/flow_graph_compiler.cc b/runtime/vm/flow_graph_compiler.cc
index 05defc90253d536af59eaf717b8ca9691450a432..264b623ade62d524a66d1fd3562d0a00c9cc2d39 100644
--- a/runtime/vm/flow_graph_compiler.cc
+++ b/runtime/vm/flow_graph_compiler.cc
@@ -199,27 +199,6 @@ bool FlowGraphCompiler::IsNextBlock(BlockEntryInstr* block_entry) const {
 }
 
 
-void FlowGraphCompiler::SaveLiveRegisters(LocationSummary* locs) {
-  // TODO(vegorov): consider saving only caller save (volatile) registers.
-  for (intptr_t reg_idx = 0; reg_idx < kNumberOfCpuRegisters; ++reg_idx) {
-    Register reg = static_cast<Register>(reg_idx);
-    if (locs->live_registers()->Contains(reg)) {
-      assembler()->PushRegister(reg);
-    }
-  }
-}
-
-
-void FlowGraphCompiler::RestoreLiveRegisters(LocationSummary* locs) {
-  for (intptr_t reg_idx = kNumberOfCpuRegisters - 1; reg_idx >= 0; --reg_idx) {
-    Register reg = static_cast<Register>(reg_idx);
-    if (locs->live_registers()->Contains(reg)) {
-      assembler()->PopRegister(reg);
-    }
-  }
-}
-
-
 void FlowGraphCompiler::AddSlowPathCode(SlowPathCode* code) {
   slow_path_code_.Add(code);
 }
@@ -648,6 +627,9 @@ void FlowGraphCompiler::AllocateRegistersLocally(Instruction* instr) {
       case Location::kSameAsFirstInput:
         result_location = locs->in(0);
         break;
+      case Location::kRequiresXmmRegister:
+        UNREACHABLE();
+        break;
     }
     locs->set_out(result_location);
   }