S390: Fix prologue offset in GeneratePrologue

src/crankshaft/s390/lithium-codegen-s390.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/crankshaft/s390/lithium-codegen-s390.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 90 matching lines @@
     // lr: Caller's pc.
     // ip: Our own function entry (required by the prologue)
   }
 
   int prologue_offset = masm_->pc_offset();
 
   if (prologue_offset) {
     // Prologue logic requires its starting address in ip and the
     // corresponding offset from the function entry.  Need to add
     // 4 bytes for the size of AHI/AGHI that AddP expands into.
-    __ AddP(ip, ip, Operand(prologue_offset + sizeof(FourByteInstr)));
+    prologue_offset += sizeof(FourByteInstr);
+    __ AddP(ip, ip, Operand(prologue_offset));
   }
   info()->set_prologue_offset(prologue_offset);
   if (NeedsEagerFrame()) {
     if (info()->IsStub()) {
       __ StubPrologue(StackFrame::STUB, ip, prologue_offset);
     } else {
       __ Prologue(info()->GeneratePreagedPrologue(), ip, prologue_offset);
     }
     frame_is_built_ = true;
   }
@@ skipping 5541 matching lines @@
 }
 
 void LCodeGen::DoStoreFrameContext(LStoreFrameContext* instr) {
   Register context = ToRegister(instr->context());
   __ StoreP(context, MemOperand(fp, StandardFrameConstants::kContextOffset));
 }
 
 #undef __
 }  // namespace internal
 }  // namespace v8