Allocation space decisions are precisely made in hydrogen.

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 929d04de13aa693065ad37067d8645266eed2300..ecca0f7ca140dcd085eca21a92151d331043be67 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -5353,10 +5353,12 @@ void LCodeGen::DoAllocate(LAllocate* instr) {
   if (instr->hydrogen()->MustAllocateDoubleAligned()) {
     flags = static_cast<AllocationFlags>(flags | DOUBLE_ALIGNMENT);
   }
-  if (instr->hydrogen()->CanAllocateInOldPointerSpace()) {
-    ASSERT(!instr->hydrogen()->CanAllocateInOldDataSpace());
+  if (instr->hydrogen()->IsOldPointerSpaceAllocation()) {
+    ASSERT(!instr->hydrogen()->IsOldDataSpaceAllocation());
+    ASSERT(!instr->hydrogen()->IsNewSpaceAllocation());
     flags = static_cast<AllocationFlags>(flags | PRETENURE_OLD_POINTER_SPACE);
-  } else if (instr->hydrogen()->CanAllocateInOldDataSpace()) {
+  } else if (instr->hydrogen()->IsOldDataSpaceAllocation()) {
+    ASSERT(!instr->hydrogen()->IsNewSpaceAllocation());
     flags = static_cast<AllocationFlags>(flags | PRETENURE_OLD_DATA_SPACE);
   }
 
@@ -5415,10 +5417,12 @@ void LCodeGen::DoDeferredAllocate(LAllocate* instr) {
     __ Push(Smi::FromInt(size));
   }
 
-  if (instr->hydrogen()->CanAllocateInOldPointerSpace()) {
-    ASSERT(!instr->hydrogen()->CanAllocateInOldDataSpace());
+  if (instr->hydrogen()->IsOldPointerSpaceAllocation()) {
+    ASSERT(!instr->hydrogen()->IsOldDataSpaceAllocation());
+    ASSERT(!instr->hydrogen()->IsNewSpaceAllocation());
     CallRuntimeFromDeferred(Runtime::kAllocateInOldPointerSpace, 1, instr);
-  } else if (instr->hydrogen()->CanAllocateInOldDataSpace()) {
+  } else if (instr->hydrogen()->IsOldDataSpaceAllocation()) {
+    ASSERT(!instr->hydrogen()->IsNewSpaceAllocation());
     CallRuntimeFromDeferred(Runtime::kAllocateInOldDataSpace, 1, instr);
   } else {
     CallRuntimeFromDeferred(Runtime::kAllocateInNewSpace, 1, instr);