diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index 58daf5d0c..3a45d58dc 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -2003,7 +2003,6 @@ static size_t ZSTD_compressBlock_internal(ZSTD_CCtx* zc,
     {   const BYTE* const base = ms->window.base;
         const BYTE* const istart = (const BYTE*)src;
         const U32 current = (U32)(istart-base);
-        assert(istart >= base);
         if (sizeof(ptrdiff_t)==8) assert(istart - base < (ptrdiff_t)(U32)(-1));   /* ensure no overflow */
         if (current > ms->nextToUpdate + 384)
             ms->nextToUpdate = current - MIN(192, (U32)(current - ms->nextToUpdate - 384));