[crankshaft] Fragmentation-free allocation folding.

src/crankshaft/arm64/lithium-arm64.cc

Index: src/crankshaft/arm64/lithium-arm64.cc
diff --git a/src/crankshaft/arm64/lithium-arm64.cc b/src/crankshaft/arm64/lithium-arm64.cc
index 45b0d030d3fdcc78c5dc82127b5b9bfece56e14c..308929d21006fec2280f68b53b49370c0c054d3d 100644
--- a/src/crankshaft/arm64/lithium-arm64.cc
+++ b/src/crankshaft/arm64/lithium-arm64.cc
@@ -841,14 +841,20 @@ LInstruction* LChunkBuilder::DoAdd(HAdd* instr) {
 
 
 LInstruction* LChunkBuilder::DoAllocate(HAllocate* instr) {
-  info()->MarkAsDeferredCalling();
-  LOperand* context = UseAny(instr->context());
   LOperand* size = UseRegisterOrConstant(instr->size());
   LOperand* temp1 = TempRegister();
   LOperand* temp2 = TempRegister();
-  LOperand* temp3 = instr->MustPrefillWithFiller() ? TempRegister() : NULL;
-  LAllocate* result = new(zone()) LAllocate(context, size, temp1, temp2, temp3);
-  return AssignPointerMap(DefineAsRegister(result));
+  if (instr->IsAllocationFolded()) {
+    LFastAllocate* result = new (zone()) LFastAllocate(size, temp1, temp2);
+    return DefineAsRegister(result);
+  } else {
+    info()->MarkAsDeferredCalling();
+    LOperand* context = UseAny(instr->context());
+    LOperand* temp3 = instr->MustPrefillWithFiller() ? TempRegister() : NULL;
+    LAllocate* result =
+        new (zone()) LAllocate(context, size, temp1, temp2, temp3);
+    return AssignPointerMap(DefineAsRegister(result));
+  }
 }