[clang] Correctly handle negative line changes (PR #166631)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Sergej Salnikov (SergejSalnikov)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/166631.diff


1 Files Affected:

- (modified) clang/lib/Frontend/PrintPreprocessedOutput.cpp (+1-1) 


``````````diff
diff --git a/clang/lib/Frontend/PrintPreprocessedOutput.cpp b/clang/lib/Frontend/PrintPreprocessedOutput.cpp
index 9e046633328d7..32e2b8cdcf4c6 100644
--- a/clang/lib/Frontend/PrintPreprocessedOutput.cpp
+++ b/clang/lib/Frontend/PrintPreprocessedOutput.cpp
@@ -306,7 +306,7 @@ bool PrintPPOutputPPCallbacks::MoveToLine(unsigned LineNo,
     *OS << '\n';
     StartedNewLine = true;
   } else if (!DisableLineMarkers) {
-    if (LineNo - CurLine <= 8) {
+    if (LineNo >= CurLine && LineNo - CurLine <= 8) {
       const char *NewLines = "\n\n\n\n\n\n\n\n";
       OS->write(NewLines, LineNo - CurLine);
     } else {

``````````

</details>


https://github.com/llvm/llvm-project/pull/166631