MachineInstr: Respect register aliases in clearRegiserKills()
This fixes bugs in copy elimination code in llvm. It slightly changes the
semantics of clearRegisterKills(). This is appropriate because:
- Users in lib/CodeGen/MachineCopyPropagation.cpp and
lib/Target/AArch64RedundantCopyElimination.cpp and
lib/Target/SystemZ/SystemZElimCompare.cpp are incorrect without it
(see included testcase).
- All other users in llvm are unaffected (they pass TRI==nullptr)
- (Kill flags are optional anyway so removing too many shouldn't hurt.)
Differential Revision: http://reviews.llvm.org/D17554
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261763 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed