[DebugInfo] Fix bug in LiveDebugVariables.
In lib/CodeGen/LiveDebugVariables.cpp, it uses std::prev(MBBI) to
get DebugValue's SlotIndex. However, the previous instruction may be
also a debug instruction. It could not use a debug instruction to query
SlotIndex in mi2iMap.
Scan all debug instructions and use the first debug instruction to query
SlotIndex for following debug instructions. Only handle DBG_VALUE in
handleDebugValue().
Differential Revision: https://reviews.llvm.org/D50621
llvm-svn: 341446
diff --git a/llvm/lib/CodeGen/LiveDebugVariables.cpp b/llvm/lib/CodeGen/LiveDebugVariables.cpp
index b258a0e..4c002d4 100644
--- a/llvm/lib/CodeGen/LiveDebugVariables.cpp
+++ b/llvm/lib/CodeGen/LiveDebugVariables.cpp
@@ -578,23 +578,28 @@
MachineBasicBlock *MBB = &*MFI;
for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
MBBI != MBBE;) {
- if (!MBBI->isDebugValue()) {
+ // Use the first debug instruction in the sequence to get a SlotIndex
+ // for following consecutive debug instructions.
+ if (!MBBI->isDebugInstr()) {
++MBBI;
continue;
}
- // DBG_VALUE has no slot index, use the previous instruction instead.
+ // Debug instructions has no slot index. Use the previous
+ // non-debug instruction's SlotIndex as its SlotIndex.
SlotIndex Idx =
MBBI == MBB->begin()
? LIS->getMBBStartIdx(MBB)
: LIS->getInstructionIndex(*std::prev(MBBI)).getRegSlot();
- // Handle consecutive DBG_VALUE instructions with the same slot index.
+ // Handle consecutive debug instructions with the same slot index.
do {
- if (handleDebugValue(*MBBI, Idx)) {
+ // Only handle DBG_VALUE in handleDebugValue(). Skip all other
+ // kinds of debug instructions.
+ if (MBBI->isDebugValue() && handleDebugValue(*MBBI, Idx)) {
MBBI = MBB->erase(MBBI);
Changed = true;
} else
++MBBI;
- } while (MBBI != MBBE && MBBI->isDebugValue());
+ } while (MBBI != MBBE && MBBI->isDebugInstr());
}
}
return Changed;