From eb1cf426c28d6e79b4adbc0b5193bd6eb82051db Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Thu, 24 Oct 2024 19:10:14 +0900
Subject: [PATCH] Tell gcc-14 that `Qnil` is not passed to `gzfile_calc_crc`

Suppress false positive warnings due to a bug in gcc-14 optimizer.
---
 ext/zlib/zlib.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/ext/zlib/zlib.c b/ext/zlib/zlib.c
index 0899861..e9535aa 100644
--- a/ext/zlib/zlib.c
+++ b/ext/zlib/zlib.c
@@ -4229,6 +4229,7 @@ gzreader_skip_linebreaks(struct gzfile *gz)
     while (n++, *(p++) == '\n') {
 	if (n >= ZSTREAM_BUF_FILLED(&gz->z)) {
 	    str = zstream_detach_buffer(&gz->z);
+	    ASSUME(!NIL_P(str));
 	    gzfile_calc_crc(gz, str);
 	    while (ZSTREAM_BUF_FILLED(&gz->z) == 0) {
 		if (GZFILE_IS_FINISHED(gz)) return;
@@ -4637,6 +4638,7 @@ zlib_gunzip_run(VALUE arg)
 
     gzfile_read_header(gz, Qnil);
     dst = zstream_detach_buffer(&gz->z);
+    ASSUME(!NIL_P(dst));
     gzfile_calc_crc(gz, dst);
     if (!ZSTREAM_IS_FINISHED(&gz->z)) {
 	rb_raise(cGzError, "unexpected end of file");