[turbofan] Try to allocate preferred register after splitting range.

src/compiler/register-allocator.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/adapters.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/register-allocator.h"
 #include "src/string-stream.h"
 
 namespace v8 {
@@ skipping 3132 matching lines @@
   if (pos <= current->Start()) {
     // All registers are blocked.
     return false;
   }
 
   if (pos < current->End()) {
     // Register reg is available at the range start but becomes blocked before
     // the range end. Split current at position where it becomes blocked.
     LiveRange* tail = SplitRangeAt(current, pos);
     AddToUnhandledSorted(tail);
+
+    // Try to allocate preferred register once more.
+    if (TryAllocatePreferredReg(current, free_until_pos)) return true;
   }
 
   // Register reg is available at the range start and is free until the range
   // end.
   DCHECK(pos >= current->End());
   TRACE("Assigning free reg %s to live range %d:%d\n", RegisterName(reg),
         current->TopLevel()->vreg(), current->relative_id());
   SetLiveRangeAssignedRegister(current, reg);
 
   return true;
@@ skipping 847 matching lines @@
         }
       }
     }
   }
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8