Clobber non-live temporaries on some paths involving a possible slow-path allocation.

runtime/vm/intermediate_language_arm64.cc

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 1852 matching lines @@
     __ b(&store_float64x2, EQ);
 
     // Fall through.
     __ b(&store_pointer);
 
     if (!compiler->is_optimizing()) {
         locs()->live_registers()->Add(locs()->in(0));
         locs()->live_registers()->Add(locs()->in(1));
     }
 
+    // Manually preserve temp which could be clobbered on the slow path.
+    locs()->live_registers()->Add(locs()->temp(0));
+
     {
       __ Bind(&store_double);
       EnsureMutableBox(compiler,
                        this,
                        temp,
                        compiler->double_class(),
                        instance_reg,
                        offset_in_bytes_,
                        temp2);
       __ LoadDFieldFromOffset(VTMP, value_reg, Double::value_offset(), PP);
@@ skipping 3708 matching lines @@
   compiler->GenerateCall(token_pos(), &label, stub_kind_, locs());
 #if defined(DEBUG)
   __ LoadImmediate(R4, kInvalidObjectPointer, kNoPP);
   __ LoadImmediate(R5, kInvalidObjectPointer, kNoPP);
 #endif
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64