A REG_SEQUENCE instruction may use the same register twice.
If we are emitting COPY instructions for the REG_SEQUENCE, make sure the kill
flag goes on the last COPY. Otherwise we may be using a killed register.
<rdar://problem/8287792>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110589 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index 2e17ebc..f58f8f5 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -1446,7 +1446,17 @@
//
// If the REG_SEQUENCE doesn't kill its source, keeping live variables
// correctly up to date becomes very difficult. Insert a copy.
- //
+
+ // Defer any kill flag to the last operand using SrcReg. Otherwise, we
+ // might insert a COPY that uses SrcReg after is was killed.
+ if (isKill)
+ for (unsigned j = i + 2; j < e; j += 2)
+ if (MI->getOperand(j).getReg() == SrcReg) {
+ MI->getOperand(j).setIsKill();
+ isKill = false;
+ break;
+ }
+
MachineBasicBlock::iterator InsertLoc = MI;
MachineInstr *CopyMI = BuildMI(*MI->getParent(), InsertLoc,
MI->getDebugLoc(), TII->get(TargetOpcode::COPY))