Subject: bug#66002: [PATCH] build: suppress suggest-attribute=cold warnings

From: Paul Eggert <[email-masked]>
Date: Fri, 15 Sep 2023 17:04:05 -0700

On 9/15/23 08:45, Gleb Fotengauer-Malinovskiy wrote:
> Following the glibc commit glibc-2.38~298 ("Mark various cold functions
> as __COLD"), GNU grep build with -flto flag triggers a GCC warning:
> 
> sigsegv.c: In function ‘stackoverflow_deinstall_handler.part.0’:
> sigsegv.c:1441:1: error: function might be candidate for attribute ‘cold’ [-Werror=suggest-attribute=cold]
> 
> * configure.ac (GNULIB_WARN_CFLAGS): Suppress -Wsuggest-attribute=cold.

I'm not seeing this problem on Fedora 38 when I manually mark error, 
error_at_line, and perror with _GL_ATTRIBUTE_COLD. I am compiling with 
gcc (GCC) 13.2.1 20230728 (Red Hat 13.2.1-1) and configuring with 
"./configure --enable-gcc-warnings 'CC=gcc -flto'". This is grep commit 
102be2bfa571355ff44db39348438a0def1ab382.

If you're using an older GCC, I wouldn't worry about the false alarm, 
whatever it's about (it's not clear from the diagnostic). The 
attribute-cold diagnostics are occasionally helpful for minor 
performance tuning, and are harmless if ignored.