[DebugInfo][RemoveDIs] Fix error from not tracking seen debug labels (#88718)

Fixes the reported errors on:
https://github.com/llvm/llvm-project/pull/87379

A previous patch updated the bitcode reading for debug
intrinsics/records to not perform the expensive debug info format
conversion from records to intrinsics in cases where no records were
present, but the patch did not actually track when debug labels had been
seen, resulting in errors when parsing bitcode where functions contained
debug label records but no other debug records. This patch fixes that
case and adds a test for it.

1 files changed, 1 insertions, 0 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index fe4f0d6..0b7fcd8 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -6454,6 +6454,7 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
     case bitc::FUNC_CODE_DEBUG_RECORD_LABEL: {
       // DbgLabelRecords are placed after the Instructions that they are
       // attached to.
+      SeenDebugRecord = true;
       Instruction *Inst = getLastInstruction();
       if (!Inst)
         return error("Invalid dbg record: missing instruction");