3 files changed, 9 insertions, 3 deletions
diff --git a/compiler/optimizing/code_generator.cc b/compiler/optimizing/code_generator.cc
index d40e2b9ad1..9c6dcaa7b3 100644
--- a/compiler/optimizing/code_generator.cc
+++ b/compiler/optimizing/code_generator.cc
@@ -291,7 +291,8 @@ void CodeGenerator::InitializeCodeGeneration(size_t number_of_spill_slots,
   DCHECK(!block_order.empty());
   DCHECK(block_order[0] == GetGraph()->GetEntryBlock());
   ComputeSpillMask();
-  first_register_slot_in_slow_path_ = (number_of_out_slots + number_of_spill_slots) * kVRegSize;
+  first_register_slot_in_slow_path_ = RoundUp(
+      (number_of_out_slots + number_of_spill_slots) * kVRegSize, GetPreferredSlotsAlignment());
 
   if (number_of_spill_slots == 0
       && !HasAllocatedCalleeSaveRegisters()
@@ -302,8 +303,7 @@ void CodeGenerator::InitializeCodeGeneration(size_t number_of_spill_slots,
     SetFrameSize(CallPushesPC() ? GetWordSize() : 0);
   } else {
     SetFrameSize(RoundUp(
-        number_of_spill_slots * kVRegSize
-        + number_of_out_slots * kVRegSize
+        first_register_slot_in_slow_path_
         + maximum_number_of_live_core_registers * GetWordSize()
         + maximum_number_of_live_fpu_registers * GetFloatingPointSpillSlotSize()
         + FrameEntrySpillSize(),
diff --git a/compiler/optimizing/code_generator.h b/compiler/optimizing/code_generator.h
index b8540baca2..47e6625d07 100644
--- a/compiler/optimizing/code_generator.h
+++ b/compiler/optimizing/code_generator.h
@@ -211,6 +211,8 @@ class CodeGenerator : public DeletableArenaObject<kArenaAllocCodeGenerator> {
                                 size_t maximum_number_of_live_fpu_registers,
                                 size_t number_of_out_slots,
                                 const ArenaVector<HBasicBlock*>& block_order);
+  // Backends can override this as necessary. For most, no special alignment is required.
+  virtual uint32_t GetPreferredSlotsAlignment() const { return 1; }
 
   uint32_t GetFrameSize() const { return frame_size_; }
   void SetFrameSize(uint32_t size) { frame_size_ = size; }
diff --git a/compiler/optimizing/code_generator_arm64.h b/compiler/optimizing/code_generator_arm64.h
index c2f055a1cf..b35c520678 100644
--- a/compiler/optimizing/code_generator_arm64.h
+++ b/compiler/optimizing/code_generator_arm64.h
@@ -418,6 +418,10 @@ class CodeGeneratorARM64 : public CodeGenerator {
     block_labels_.resize(GetGraph()->GetBlocks().size());
   }
 
+  // We want to use the STP and LDP instructions to spill and restore registers for slow paths.
+  // These instructions can only encode offsets that are multiples of the register size accessed.
+  uint32_t GetPreferredSlotsAlignment() const OVERRIDE { return vixl::kXRegSizeInBytes; }
+
   JumpTableARM64* CreateJumpTable(HPackedSwitch* switch_instr) {
     jump_tables_.emplace_back(new (GetGraph()->GetArena()) JumpTableARM64(switch_instr));
     return jump_tables_.back().get();