Merge ConstantInstr -> UnboxDouble to UnboxedConstant. Reduces register usage and allows for variou…

runtime/vm/flow_graph_compiler_ia32.cc

Index: runtime/vm/flow_graph_compiler_ia32.cc
===================================================================
--- runtime/vm/flow_graph_compiler_ia32.cc	(revision 35656)
+++ runtime/vm/flow_graph_compiler_ia32.cc	(working copy)
@@ -12,6 +12,7 @@
 #include "vm/cpu.h"
 #include "vm/dart_entry.h"
 #include "vm/deopt_instructions.h"
+#include "vm/flow_graph_builder.h"
 #include "vm/il_printer.h"
 #include "vm/locations.h"
 #include "vm/object_store.h"
@@ -1649,6 +1650,18 @@
       } else {
         __ LoadObjectSafely(destination.reg(), constant);
       }
+    } else if (destination.IsFpuRegister()) {
+      const Double& constant = Double::Cast(source.constant());
+      uword addr = FlowGraphBuilder::FindDoubleConstant(constant.value());
+      if (addr == 0) {
+        __ pushl(EAX);
+        __ LoadObject(EAX, constant);
+        __ movsd(destination.fpu_reg(),
+            FieldAddress(EAX, Double::value_offset()));
+        __ popl(EAX);
+      } else {
+        __ movsd(destination.fpu_reg(), Address::Absolute(addr));
+      }
     } else {
       ASSERT(destination.IsStackSlot());
       StoreObject(destination.ToStackSlotAddress(), source.constant());