[turbofan] splinters should spill if there is no register use

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 2643 matching lines @@
     }
 
     DCHECK(!current->HasRegisterAssigned() && !current->spilled());
 
     ProcessCurrentRange(current);
   }
 }
 
 bool LinearScanAllocator::TrySplitAndSpillSplinter(LiveRange* range) {
   DCHECK(range->TopLevel()->IsSplinter());
-  // If there was no hint, apply regular (hot path) heuristics.
-  if (range->FirstHintPosition() == nullptr) return false;
   // If we can spill the whole range, great. Otherwise, split above the
   // first use needing a register and spill the top part.
   const UsePosition* next_reg = range->NextRegisterPosition(range->Start());
   if (next_reg == nullptr) {
     Spill(range);
     return true;
+  } else if (range->FirstHintPosition() == nullptr) {
+    // If there was no hint, but we have a use position requiring a
+    // register, apply the hot path heuristics.
+    return false;
   } else if (next_reg->pos().PrevStart() > range->Start()) {
     LiveRange* tail = SplitRangeAt(range, next_reg->pos().PrevStart());
     AddToUnhandledSorted(tail);
     Spill(range);
     return true;
   }
   return false;
 }
 
 void LinearScanAllocator::SetLiveRangeAssignedRegister(LiveRange* range,
@@ skipping 1033 matching lines @@
         }
       }
     }
   }
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8