[turbofan] Use special constant type for RPO block number operands.

src/compiler/mips64/code-generator-mips64.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/code-generator.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties-inl.h"
 #include "src/mips/macro-assembler-mips.h"
@@ skipping 53 matching lines @@
         return Operand(
             isolate()->factory()->NewNumber(constant.ToFloat32(), TENURED));
       case Constant::kFloat64:
         return Operand(
             isolate()->factory()->NewNumber(constant.ToFloat64(), TENURED));
       case Constant::kExternalReference:
       case Constant::kHeapObject:
         // TODO(plind): Maybe we should handle ExtRef & HeapObj here?
         //    maybe not done on arm due to const pool ??
         break;
+      case Constant::kRpoNumber:
+        UNREACHABLE();  // TODO(titzer): RPO immediates on mips?
+        break;
     }
     UNREACHABLE();
     return Operand(zero_reg);
   }
 
   Operand InputOperand(int index) {
     InstructionOperand* op = instr_->InputAt(index);
     if (op->IsRegister()) {
       return Operand(ToRegister(op));
     }
@@ skipping 980 matching lines @@
           break;
         case Constant::kFloat64:
           __ li(dst, isolate()->factory()->NewNumber(src.ToFloat64(), TENURED));
           break;
         case Constant::kExternalReference:
           __ li(dst, Operand(src.ToExternalReference()));
           break;
         case Constant::kHeapObject:
           __ li(dst, src.ToHeapObject());
           break;
+        case Constant::kRpoNumber:
+          UNREACHABLE();  // TODO(titzer): loading RPO numbers on mips64.
+          break;
       }
       if (destination->IsStackSlot()) __ sd(dst, g.ToMemOperand(destination));
     } else if (src.type() == Constant::kFloat32) {
       FPURegister dst = destination->IsDoubleRegister()
                             ? g.ToDoubleRegister(destination)
                             : kScratchDoubleReg.low();
       // TODO(turbofan): Can we do better here?
       __ li(at, Operand(bit_cast<int32_t>(src.ToFloat32())));
       __ mtc1(at, dst);
       if (destination->IsDoubleStackSlot()) {
@@ skipping 127 matching lines @@
     }
   }
   MarkLazyDeoptSite();
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8