Use (more) xor on FP register to load it with 0.0.

runtime/vm/flow_graph_compiler_arm64.cc

Index: runtime/vm/flow_graph_compiler_arm64.cc
===================================================================
--- runtime/vm/flow_graph_compiler_arm64.cc	(revision 38628)
+++ runtime/vm/flow_graph_compiler_arm64.cc	(working copy)
@@ -1585,12 +1585,20 @@
       __ LoadObject(destination.reg(), constant, PP);
     } else if (destination.IsFpuRegister()) {
       const VRegister dst = destination.fpu_reg();
-      __ LoadObject(TMP, constant, PP);
-      __ LoadDFieldFromOffset(dst, TMP, Double::value_offset(), PP);
+      if (Utils::DoublesBitEqual(Double::Cast(constant).value(), 0.0)) {
+        __ veor(dst, dst, dst);
+      } else {
+        __ LoadObject(TMP, constant, PP);
+        __ LoadDFieldFromOffset(dst, TMP, Double::value_offset(), PP);
+      }
     } else if (destination.IsDoubleStackSlot()) {
+      if (Utils::DoublesBitEqual(Double::Cast(constant).value(), 0.0)) {
+        __ veor(VTMP, VTMP, VTMP);
+      } else {
+        __ LoadObject(TMP, constant, PP);
+        __ LoadDFieldFromOffset(VTMP, TMP, Double::value_offset(), PP);
+      }
       const intptr_t dest_offset = destination.ToStackSlotOffset();
-      __ LoadObject(TMP, constant, PP);
-      __ LoadDFieldFromOffset(VTMP, TMP, Double::value_offset(), PP);
       __ StoreDToOffset(VTMP, FP, dest_offset, PP);
     } else {
       ASSERT(destination.IsStackSlot());