[turbofan] put gaps before instructions

src/compiler/code-generator.cc

 // Copyright 2013 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/linkage.h"
 #include "src/compiler/pipeline.h"
 
@@ skipping 115 matching lines @@
       safepoint.DefinePointerRegister(reg, zone());
     }
   }
 }
 
 
 void CodeGenerator::AssembleInstruction(Instruction* instr) {
   if (instr->IsGapMoves()) {
     // Handle parallel moves associated with the gap instruction.
     AssembleGap(GapInstruction::cast(instr));
+  } else if (instr->IsBlockStart()) {
+    return;
   } else if (instr->IsSourcePosition()) {
     AssembleSourcePosition(SourcePositionInstruction::cast(instr));
   } else {
     // Assemble architecture-specific code for the instruction.
     AssembleArchInstruction(instr);
 
     // Assemble branches or boolean materializations after this instruction.
     FlagsMode mode = FlagsModeField::decode(instr->opcode());
     FlagsCondition condition = FlagsConditionField::decode(instr->opcode());
     switch (mode) {
@@ skipping 379 matching lines @@
 }
 
 
 void CodeGenerator::AddNopForSmiCodeInlining() { UNIMPLEMENTED(); }
 
 #endif  // !V8_TURBOFAN_BACKEND
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8