diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
index 08d116a..9647e83 100644
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -76,7 +76,13 @@
 }
 
 MachineFunction::~MachineFunction() {
-  BasicBlocks.clear();
+  // Don't call destructors on MachineInstr and MachineOperand. All of their
+  // memory comes from the BumpPtrAllocator which is about to be purged.
+  //
+  // Do call MachineBasicBlock destructors, it contains std::vectors.
+  for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
+    I->Insts.clearAndLeakNodesUnsafely();
+
   InstructionRecycler.clear(Allocator);
   OperandRecycler.clear(Allocator);
   BasicBlockRecycler.clear(Allocator);
@@ -176,15 +182,17 @@
 
 /// DeleteMachineInstr - Delete the given MachineInstr.
 ///
+/// This function also serves as the MachineInstr destructor - the real
+/// ~MachineInstr() destructor must be empty.
 void
 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
   // Strip it for parts. The operand array and the MI object itself are
   // independently recyclable.
   if (MI->Operands)
     deallocateOperandArray(MI->CapOperands, MI->Operands);
-  MI->Operands = 0;
-  MI->NumOperands = 0;
-  MI->~MachineInstr();
+  // Don't call ~MachineInstr() which must be trivial anyway because
+  // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
+  // destructors.
   InstructionRecycler.Deallocate(Allocator, MI);
 }