[turbofan] Fewer gap moves for tail calls

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/ast/scopes.h"
 #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/osr.h"
@@ skipping 448 matching lines @@
     __ cvt_s_w(i.OutputDoubleRegister(), i.OutputDoubleRegister());           \
     __ bind(ool->exit());                                                     \
     __ bind(&done);                                                           \
   } while (0)
 
 void CodeGenerator::AssembleDeconstructActivationRecord(int stack_param_delta) {
   int sp_slot_delta = TailCallFrameStackSlotDelta(stack_param_delta);
   if (sp_slot_delta > 0) {
     __ daddiu(sp, sp, sp_slot_delta * kPointerSize);
   }
-  if (frame()->needs_frame()) {
-    __ Pop(ra, fp);
-  }
   frame_access_state()->SetFrameAccessToDefault();
 }
 
 
 void CodeGenerator::AssemblePrepareTailCall(int stack_param_delta) {
   int sp_slot_delta = TailCallFrameStackSlotDelta(stack_param_delta);
   if (sp_slot_delta < 0) {
     __ Dsubu(sp, sp, Operand(-sp_slot_delta * kPointerSize));
     frame_access_state()->IncreaseSPDelta(-sp_slot_delta);
   }
+  if (frame()->needs_frame()) {
+    __ ld(ra, MemOperand(fp, StandardFrameConstants::kCallerPCOffset));
+    __ ld(fp, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+  }
   frame_access_state()->SetFrameAccessToSP();
 }
 
 
 // Assembles an instruction after register allocation, producing machine code.
 void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
   MipsOperandConverter i(this, instr);
   InstructionCode opcode = instr->opcode();
 
   switch (ArchOpcodeField::decode(opcode)) {
@@ skipping 1273 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8