If only user of a vreg is an copy instruction to export copy of vreg out of current basic block then insert DBG_VALUE so that debug value of the variable is also transfered to new vreg.
Testcase is in r114476.
This fixes radar 8412415.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114478 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index a754ac2..7ec1492 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -290,6 +290,29 @@
TII.get(TargetOpcode::DBG_VALUE))
.addReg(LDI->second, RegState::Debug)
.addImm(Offset).addMetadata(Variable);
+
+ // If this vreg is directly copied into an exported register then
+ // that COPY instructions also need DBG_VALUE, if it is the only
+ // user of LDI->second.
+ MachineInstr *CopyUseMI = NULL;
+ for (MachineRegisterInfo::use_iterator
+ UI = RegInfo->use_begin(LDI->second);
+ MachineInstr *UseMI = UI.skipInstruction();) {
+ if (UseMI->isDebugValue()) continue;
+ if (UseMI->isCopy() && !CopyUseMI && UseMI->getParent() == EntryMBB) {
+ CopyUseMI = UseMI; continue;
+ }
+ // Otherwise this is another use or second copy use.
+ CopyUseMI = NULL; break;
+ }
+ if (CopyUseMI) {
+ MachineInstr *NewMI =
+ BuildMI(*MF, CopyUseMI->getDebugLoc(),
+ TII.get(TargetOpcode::DBG_VALUE))
+ .addReg(CopyUseMI->getOperand(0).getReg(), RegState::Debug)
+ .addImm(Offset).addMetadata(Variable);
+ EntryMBB->insertAfter(CopyUseMI, NewMI);
+ }
}
}