Subject: Re: bug#72036: 31.0.50; master doesn't build on macOS with clang 18

From: Pip Cet <[email-masked]>
Date: Wed, 10 Jul 2024 15:38:56 +0000

(CC'ing Paul Eggert and Jim Meyering, the relevant gnulib maintainers).

On Wednesday, July 10th, 2024 at 14:09, Gerd Möllmann <[email-masked]> wrote:
> master, HEAD a29a385ee5ea938ed17d94622c7bfd0a10e84830
> 
> timespec-sub.c:38:12: error: operand argument to checked integer operation must be an integer type
> other than plain 'char', 'bool', bit-precise, or an enumeration ('bool' invalid)
> 38 | if (v == ckd_sub (&rs, rs, borrow))
>    |          ^~~~~~~~~~~~~~~~~~~~~~~~~
> /opt/homebrew/Cellar/llvm/18.1.8/lib/clang/18/include/stdckdint.h:38:54: note: expanded from macro
> 'ckd_sub'
> 38 | #define ckd_sub(R, A, B) __builtin_sub_overflow((A), (B), (R))
>    |                                                      ^~~

The attached patch to gnulib helps here. I'm using clang version 18.1.8 and the testdir-all build fails if I ./configure CC=clang.

Pip

From e8400f61b74327c1b7f370b746d282b04355e287 Mon Sep 17 00:00:00 2001
From: Philip Russell <[email-masked]>
Date: Wed, 10 Jul 2024 15:33:05 +0000
Subject: [PATCH] timespec-sub: Fix compilation error on clang.

*lib/timespec-sub.c (timespec_sub): Use 'int' as type of variable.
---
 ChangeLog          | 5 +++++
 lib/timespec-sub.c | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 21db18416b..aec37eef48 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2024-07-10  Pip Cet  <[email-masked]>
+
+	timespec-sub: Fix compilation error on clang.
+	* lib/timespec-sub.c (timespec_sub): Use 'int' as type of variable.
+
 2024-07-06  Bruno Haible  <[email-masked]>
 
 	pthread-cond: Fix compilation error on native Windows.
diff --git a/lib/timespec-sub.c b/lib/timespec-sub.c
index f6d948780e..38f9c6a4dc 100644
--- a/lib/timespec-sub.c
+++ b/lib/timespec-sub.c
@@ -31,7 +31,7 @@ struct timespec
 timespec_sub (struct timespec a, struct timespec b)
 {
   int nsdiff = a.tv_nsec - b.tv_nsec;
-  bool borrow = nsdiff < 0;
+  int borrow = nsdiff < 0;
   time_t rs;
   int rns;
   bool v = ckd_sub (&rs, a.tv_sec, b.tv_sec);
-- 
2.45.2