Set register kill flags on the SelectionDAG path, at least in the
easy cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102678 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index f857a1c..e944dfd 100644
--- a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -296,8 +296,19 @@
}
}
+ // If this value has only one use, that use is a kill. This is a
+ // conservative approximation. Tied operands are never killed, so we need
+ // to check that. And that means we need to determine the index of the
+ // operand.
+ unsigned Idx = MI->getNumOperands();
+ while (Idx > 0 &&
+ MI->getOperand(Idx-1).isReg() && MI->getOperand(Idx-1).isImplicit())
+ --Idx;
+ bool isTied = MI->getDesc().getOperandConstraint(Idx, TOI::TIED_TO) != -1;
+ bool isKill = Op.hasOneUse() && !isTied;
+
MI->addOperand(MachineOperand::CreateReg(VReg, isOptDef,
- false/*isImp*/, false/*isKill*/,
+ false/*isImp*/, isKill,
false/*isDead*/, false/*isUndef*/,
false/*isEarlyClobber*/,
0/*SubReg*/, IsDebug));