[turbofan] phis cannot take registers as inputs

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/compiler/linkage.h"
 #include "src/compiler/pipeline-statistics.h"
 #include "src/compiler/register-allocator.h"
 #include "src/string-stream.h"
 
 namespace v8 {
@@ skipping 1507 matching lines @@
       // TODO(bmeurer): This is a horrible hack to make sure that for constant
       // live ranges, every use requires the constant to be in a register.
       // Without this hack, all uses with "any" policy would get the constant
       // operand assigned.
       LiveRange* range = live_ranges_[i];
       if (range->HasAllocatedSpillOperand() &&
           range->GetSpillOperand()->IsConstant()) {
         for (UsePosition* pos = range->first_pos(); pos != NULL;
              pos = pos->next_) {
           pos->register_beneficial_ = true;
-          pos->requires_reg_ = true;
+          // TODO(dcarney): should the else case assert requires_reg_ == false?
+          // Can't mark phis as needing a register.
+          if (!code()
+                   ->InstructionAt(pos->pos().InstructionIndex())
+                   ->IsGapMoves()) {
+            pos->requires_reg_ = true;
+          }
         }
       }
     }
   }
 }
 
 
 bool RegisterAllocator::SafePointsAreInOrder() const {
   int safe_point = 0;
   const PointerMapDeque* pointer_maps = code()->pointer_maps();
@@ skipping 773 matching lines @@
   } else {
     DCHECK(range->Kind() == GENERAL_REGISTERS);
     assigned_registers_->Add(reg);
   }
   range->set_assigned_register(reg, code_zone());
 }
 
 }
 }
 }  // namespace v8::internal::compiler