From 7f9b7ccf0c14ee0dafb71860a94df65d08f59f2a Mon Sep 17 00:00:00 2001
From: Martin Liska <mliska@suse.cz>
Date: Fri, 12 Mar 2021 13:37:06 +0100
Subject: [PATCH] LTO: fallback to -flto=N if -flto=jobserver does not work.

gcc/ChangeLog:

	* lto-wrapper.c (run_gcc): When -flto=jobserver is used, but the
	makeserver cannot be detected, then use -flto=N fallback.
---
 gcc/lto-wrapper.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gcc/lto-wrapper.c b/gcc/lto-wrapper.c
index ea68490163df..6ba401007f65 100644
--- a/gcc/lto-wrapper.c
+++ b/gcc/lto-wrapper.c
@@ -1483,8 +1483,9 @@ run_gcc (unsigned argc, char *argv[])
       if (jobserver && jobserver_error != NULL)
 	{
 	  warning (0, jobserver_error);
-	  parallel = 0;
+	  /* Fall back to auto parallelism.  */
 	  jobserver = 0;
+	  auto_parallel = 1;
 	}
       else if (!jobserver && jobserver_error == NULL)
 	{
-- 
2.47.2