Allocation space decisions are precisely made in hydrogen.

src/mips/lithium-codegen-mips.cc

Index: src/mips/lithium-codegen-mips.cc
diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index 8db5f00fbffc9ad801d389ec6e2c32c8cf958051..710edf18ad53c013d55254872187ddd6a423567c 100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -5330,10 +5330,12 @@ 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);
   }
   if (instr->size()->IsConstantOperand()) {
@@ -5391,10 +5393,12 @@ 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);