Fix more -Werror=sign-compare bugs with GCC 4.9.2

src/compiler/frame-elider.cc

 // Copyright 2015 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/frame-elider.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 30 matching lines @@
   for (auto block : instruction_blocks()) {
     if (block->needs_frame()) {
       // Special case: The start block needs a frame.
       if (block->predecessors().empty()) {
         block->mark_must_construct_frame();
       }
       // Find "frame -> no frame" transitions, inserting frame
       // deconstructions.
       for (auto succ : block->successors()) {
         if (!InstructionBlockAt(succ)->needs_frame()) {
-          DCHECK_EQ(1, block->SuccessorCount());
+          DCHECK_EQ(1U, block->SuccessorCount());
           block->mark_must_deconstruct_frame();
         }
       }
     } else {
       // Find "no frame -> frame" transitions, inserting frame constructions.
       for (auto succ : block->successors()) {
         if (InstructionBlockAt(succ)->needs_frame()) {
-          DCHECK_NE(1, block->SuccessorCount());
+          DCHECK_NE(1U, block->SuccessorCount());
           InstructionBlockAt(succ)->mark_must_construct_frame();
         }
       }
     }
   }
 }
 
 
 bool FrameElider::PropagateInOrder() {
   bool changed = false;
@@ skipping 51 matching lines @@
 }
 
 
 Instruction* FrameElider::InstructionAt(int index) const {
   return code_->InstructionAt(index);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8