[turbofan] Skip printing of empty gap moves.

src/compiler/instruction.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/common-operator.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/instruction.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 269 matching lines @@
     if (i > 0) os << ", ";
     printable_op.op_ = instr.OutputAt(i);
     os << printable_op;
   }
 
   if (instr.OutputCount() > 1) os << ") = ";
   if (instr.OutputCount() == 1) os << " = ";
 
   if (instr.IsGapMoves()) {
     const GapInstruction* gap = GapInstruction::cast(&instr);
-    os << "gap ";
-    for (int i = GapInstruction::FIRST_INNER_POSITION;
-         i <= GapInstruction::LAST_INNER_POSITION; i++) {
-      os << "(";
-      if (gap->parallel_moves_[i] != NULL) {
-        PrintableParallelMove ppm = {printable.register_configuration_,
-                                     gap->parallel_moves_[i]};
-        os << ppm;
+    if (!gap->IsRedundant()) {
+      os << "gap ";
+      for (int i = GapInstruction::FIRST_INNER_POSITION;
+           i <= GapInstruction::LAST_INNER_POSITION; i++) {
+        os << "(";
+        if (gap->parallel_moves_[i] != NULL) {
+          PrintableParallelMove ppm = {printable.register_configuration_,
+                                       gap->parallel_moves_[i]};
+          os << ppm;
+        }
+        os << ") ";
       }
-      os << ") ";
     }
   } else if (instr.IsSourcePosition()) {
     const SourcePositionInstruction* pos =
         SourcePositionInstruction::cast(&instr);
     os << "position (" << pos->source_position().raw() << ")";
   } else {
     os << ArchOpcodeField::decode(instr.opcode());
     AddressingMode am = AddressingModeField::decode(instr.opcode());
     if (am != kMode_None) {
       os << " : " << AddressingModeField::decode(instr.opcode());
@@ skipping 384 matching lines @@
       os << " B" << succ_block->id();
     }
     os << "\n";
   }
   return os;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8