diff --git a/configure.ac b/configure.ac
index 2b2f9468d..f33c10ccc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -262,6 +262,10 @@ if test $gl_gcc_warnings != no; then
   # FP in careadlinkat.c w/gcc 10.0.1 20200205
   gl_WARN_ADD([-Wno-return-local-addr])
 
+  # FIXME: remove this line when gcc -O0 improves
+  # FP in nstrftime.c w/gcc 12.2.1 20221121
+  gl_WARN_ADD([-Wno-stringop-overflow])
+
   gl_MANYWARN_COMPLEMENT([GNULIB_WARN_CFLAGS], [$WARN_CFLAGS], [$nw])
   AC_SUBST([GNULIB_WARN_CFLAGS])
 
diff --git a/src/digest.c b/src/digest.c
index 6ee8a4854..3c1d27f9a 100644
--- a/src/digest.c
+++ b/src/digest.c
@@ -1125,6 +1125,7 @@ hex_equal (unsigned char const *hex_digest, unsigned char const *bin_buffer)
   return cnt == digest_bin_bytes;
 }
 
+# pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
 static bool
 digest_check (char const *checkfile_name)
 {
diff --git a/src/pr.c b/src/pr.c
index 28a695242..75ce756ae 100644
--- a/src/pr.c
+++ b/src/pr.c
@@ -2422,7 +2422,7 @@ static bool
 read_line (COLUMN *p)
 {
   int c;
-  int chars;
+  int chars=0;
   int last_input_position;
   int j, k;
   COLUMN *q;
diff --git a/src/sort.c b/src/sort.c
index 8ca7a88c4..15f06e7d8 100644
--- a/src/sort.c
+++ b/src/sort.c
@@ -1045,7 +1045,7 @@ pipe_fork (int pipefds[2], size_t tries)
   struct tempnode *saved_temphead;
   int saved_errno;
   double wait_retry = 0.25;
-  pid_t pid;
+  pid_t pid = -1;
   struct cs_status cs;
 
   if (pipe2 (pipefds, O_CLOEXEC) < 0)