AArch64: Don't call getIterator() on iterators

Remove an unnecessary round-trip:

    iterator => operator->() => getIterator()

In some cases, the iterator is end(), so the dereference of operator->
is invalid (UB).

The testcase only crashes with r278974 (currently reverted to
investigate this), which adds an assertion for invalid dereferences of
ilist nodes.

Fixes PR29035.

llvm-svn: 279104

1 files changed, 1 insertions, 2 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64RedundantCopyElimination.cpp b/llvm/lib/Target/AArch64/AArch64RedundantCopyElimination.cpp
index 26a1f5d7047..9e916ef8dd7 100644
--- a/llvm/lib/Target/AArch64/AArch64RedundantCopyElimination.cpp
+++ b/llvm/lib/Target/AArch64/AArch64RedundantCopyElimination.cpp
@@ -156,8 +156,7 @@ bool AArch64RedundantCopyElimination::optimizeCopy(MachineBasicBlock *MBB) {
     MBB->addLiveIn(TargetReg);
 
   // Clear any kills of TargetReg between CompBr and the last removed COPY.
-  for (MachineInstr &MMI :
-       make_range(MBB->begin()->getIterator(), LastChange->getIterator()))
+  for (MachineInstr &MMI : make_range(MBB->begin(), LastChange))
     MMI.clearRegisterKills(SmallestDef, TRI);
 
   return true;