Richard W.M. Jones wrote:
Could this be a bug in GCC? It's turning 2^63-1 into -1 without even issuing a warning ...
Yes, it's a GCC bug. I filed a bug report here: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81650 I installed the attached patch into Gnulib to work around the bug.
From dbeec5dcb3dadd92773caae94fe57b921c4c86e8 Mon Sep 17 00:00:00 2001 From: Paul Eggert <egg...@cs.ucla.edu> Date: Tue, 1 Aug 2017 09:52:40 -0700 Subject: [PATCH] manywarnings: port to 32-bit GCC bug Problem reported by Pino Toscano in: http://lists.gnu.org/archive/html/bug-gnulib/2017-07/msg00150.html * m4/manywarnings.m4 (gl_MANYWARN_ALL_GCC): Use 2**31 - 1, not 2**63 - 1, to work around the following GCC bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81650 --- ChangeLog | 9 +++++++++ m4/manywarnings.m4 | 6 +++--- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/ChangeLog b/ChangeLog index 7aedb71..44bdf79 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,12 @@ +2017-08-01 Paul Eggert <egg...@cs.ucla.edu> + + manywarnings: port to 32-bit GCC bug + Problem reported by Pino Toscano in: + http://lists.gnu.org/archive/html/bug-gnulib/2017-07/msg00150.html + * m4/manywarnings.m4 (gl_MANYWARN_ALL_GCC): Use 2**31 - 1, + not 2**63 - 1, to work around the following GCC bug: + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81650 + 2017-07-30 Paul Eggert <egg...@cs.ucla.edu> backupfile: new function to validate backup suffix diff --git a/m4/manywarnings.m4 b/m4/manywarnings.m4 index 2d35eff..6cf1be7 100644 --- a/m4/manywarnings.m4 +++ b/m4/manywarnings.m4 @@ -1,4 +1,4 @@ -# manywarnings.m4 serial 8 +# manywarnings.m4 serial 9 dnl Copyright (C) 2008-2017 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -259,8 +259,8 @@ AC_DEFUN([gl_MANYWARN_ALL_GCC], # gcc --help=warnings outputs an unusual form for these options; list # them here so that the above 'comm' command doesn't report a false match. # Would prefer "min (PTRDIFF_MAX, SIZE_MAX)", but it must be a literal: - ptrdiff_max_max=9223372036854775807 - gl_manywarn_set="$gl_manywarn_set -Walloc-size-larger-than=$ptrdiff_max_max" + ptrdiff_max_min=2147483647 + gl_manywarn_set="$gl_manywarn_set -Walloc-size-larger-than=$ptrdiff_max_min" gl_manywarn_set="$gl_manywarn_set -Warray-bounds=2" gl_manywarn_set="$gl_manywarn_set -Wformat-overflow=2" gl_manywarn_set="$gl_manywarn_set -Wformat-truncation=2" -- 2.7.4
