PPC: Reland "Merge old data and pointer space."

src/ppc/macro-assembler-ppc.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 <assert.h>  // For assert
 #include <limits.h>  // For LONG_MIN, LONG_MAX.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_PPC
@@ skipping 1350 matching lines @@
       cmp(result, ip);
       Check(eq, kUnexpectedAllocationTop);
     }
     // Load allocation limit into ip. Result already contains allocation top.
     LoadP(ip, MemOperand(topaddr, limit - top), r0);
   }
 
   if ((flags & DOUBLE_ALIGNMENT) != 0) {
     // Align the next allocation. Storing the filler map without checking top is
     // safe in new-space because the limit of the heap is aligned there.
-    DCHECK((flags & PRETENURE_OLD_SPACE) == 0);
 #if V8_TARGET_ARCH_PPC64
     STATIC_ASSERT(kPointerAlignment == kDoubleAlignment);
 #else
     STATIC_ASSERT(kPointerAlignment * 2 == kDoubleAlignment);
     andi(scratch2, result, Operand(kDoubleAlignmentMask));
     Label aligned;
     beq(&aligned, cr0);
     if ((flags & PRETENURE) != 0) {
       cmpl(result, ip);
       bge(gc_required);
@@ skipping 78 matching lines @@
       cmp(result, ip);
       Check(eq, kUnexpectedAllocationTop);
     }
     // Load allocation limit into ip. Result already contains allocation top.
     LoadP(ip, MemOperand(topaddr, limit - top));
   }
 
   if ((flags & DOUBLE_ALIGNMENT) != 0) {
     // Align the next allocation. Storing the filler map without checking top is
     // safe in new-space because the limit of the heap is aligned there.
-    DCHECK((flags & PRETENURE_OLD_SPACE) == 0);
 #if V8_TARGET_ARCH_PPC64
     STATIC_ASSERT(kPointerAlignment == kDoubleAlignment);
 #else
     STATIC_ASSERT(kPointerAlignment * 2 == kDoubleAlignment);
     andi(scratch2, result, Operand(kDoubleAlignmentMask));
     Label aligned;
     beq(&aligned, cr0);
     if ((flags & PRETENURE) != 0) {
       cmpl(result, ip);
       bge(gc_required);
@@ skipping 3045 matching lines @@
   }
   if (mag.shift > 0) srawi(result, result, mag.shift);
   ExtractBit(r0, dividend, 31);
   add(result, result, r0);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_PPC