diff --git a/src/regexp_bt.c b/src/regexp_bt.c
index 5f5e58f..4082f59 100644
--- a/src/regexp_bt.c
+++ b/src/regexp_bt.c
@@ -4615,6 +4615,11 @@
 			    if (rex.input == rex.line)
 			    {
 				// backup to last char of previous line
+				if (rex.lnum == 0)
+				{
+				    status = RA_NOMATCH;
+				    break;
+				}
 				--rex.lnum;
 				rex.line = reg_getline(rex.lnum);
 				// Just in case regrepeat() didn't count