1 files changed, 1 insertions, 1 deletions
diff --git a/regex.c b/regex.c
index 668773fb49..d4c1c2a915 100644
--- a/regex.c
+++ b/regex.c
@@ -2395,7 +2395,7 @@ re_compile_pattern(pattern, size, bufp)
       bufp->must = laststart+1;
     }
   }
-  else {
+  if (!bufp->must) {
     bufp->must = calculate_must_string(bufp->buffer, b);
   }
   if (current_mbctype == MBCTYPE_SJIS) bufp->options |= RE_OPTIMIZE_NO_BM;