Add a utility function for conservatively clearing kill flags, and make

use of it in MachineCSE.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103726 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h
index 905be96c35..131231e5ba 100644
--- a/include/llvm/CodeGen/MachineRegisterInfo.h
+++ b/include/llvm/CodeGen/MachineRegisterInfo.h
@@ -162,6 +162,12 @@ public:
   /// register or null if none is found.  This assumes that the code is in SSA
   /// form, so there should only be one definition.
   MachineInstr *getVRegDef(unsigned Reg) const;
+
+  /// clearKillFlags - Iterate over all the uses of the given register and
+  /// clear the kill flag from the MachineOperand. This function is used by
+  /// optimization passes which extend register lifetimes and need only
+  /// preserve conservative kill flag information.
+  void clearKillFlags(unsigned Reg) const;
   
 #ifndef NDEBUG
   void dumpUses(unsigned RegNo) const;