Fix PR26655: Bail out if all regs of an inst BUNDLE have the correct kill flag

Summary:
While setting kill flags on instructions inside a BUNDLE, we bail out as soon
as we set kill flag on a register.  But we are missing a check when all the
registers already have the correct kill flag set. We need to bail out in that
case as well.

This patch refactors the old code and simply makes use of the addRegisterKilled
function in MachineInstr.cpp in order to determine whether to set/remove kill
on an instruction.

Reviewers: apazos, t.p.northover, pete, MatzeB

Subscribers: MatzeB, davide, llvm-commits

Differential Revision: http://reviews.llvm.org/D17356

llvm-svn: 269092

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index 6b46cb356c2..8e8af1b37b3 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -1952,6 +1952,13 @@ bool MachineInstr::addRegisterKilled(unsigned IncomingReg,
     MachineOperand &MO = getOperand(i);
     if (!MO.isReg() || !MO.isUse() || MO.isUndef())
       continue;
+
+    // DEBUG_VALUE nodes do not contribute to code generation and should
+    // always be ignored. Failure to do so may result in trying to modify
+    // KILL flags on DEBUG_VALUE nodes.
+    if (MO.isDebug())
+      continue;
+
     unsigned Reg = MO.getReg();
     if (!Reg)
       continue;