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

[Sergej Salnikov via cfe-commits]

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

None

>From a53cdabdd7fcf83c2377cf78f2848c1f795c7b2c Mon Sep 17 00:00:00 2001
From: Sergej Salnikov <skill at google.com>
Date: Wed, 5 Nov 2025 21:25:04 +0100
Subject: [PATCH] Correctly handle negative line changes

---
 clang/lib/Frontend/PrintPreprocessedOutput.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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 {