test failure on FreeBSD 12.0
Bruno Haible <[email protected]>
| Newsgroups | gmane.comp.gnu.m4.bugs |
|---|---|
| Message-ID | <2875476.t2r7yGXgoR@omega> |
Hi, On FreeBSD 12.0/x86, the newest release m4-1.4.18 and the newest snapshot from https://gitlab.com/gnu-m4/ci-distcheck/ both exhibit a "make check" failure: Checking ../../checks/189.eval @ ../doc/m4.texi:6405: Origin of test ../../checks/189.eval: stdout mismatch --- m4-tmp.17036/m4-xout 2020-05-03 02:14:13.289357000 +0200 +++ m4-tmp.17036/m4-out 2020-05-03 02:14:13.279345000 +0200 @@ -2,8 +2,8 @@ 1 1 -overflow occurred --2147483648 + +2147483648 0 -2 -2 ... Failed checks were: ../../checks/189.eval:out *** Error code 1 Simplified test case: $ cat > in <<EOF define(`max_int', eval(`0x7fffffff')) define(`min_int', incr(max_int)) min_int EOF $ m4 < in Expected output: -2147483648 Actual output on FreeBSD: 2147483648 The bug occurs if and only if the source file builtin.c is compiled with optimization -O2 or higher. The attached patch (for the 'branch-1.4' branch) fixes the issue. Bruno
0001-Work-around-a-compiler-optimization-bug-on-FreeBSD-1.patch
(text/x-patch, 1.1 KB)
From aaa68d60ab6c84783cf050a9e43aa6f40c81e4df Mon Sep 17 00:00:00 2001 From: Bruno Haible <[email protected]> Date: Sun, 3 May 2020 03:00:46 +0200 Subject: [PATCH] Work around a compiler optimization bug on FreeBSD 12.0. * src/builtin.c (ntoa): Declare value parameter as 'volatile'. --- src/builtin.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/src/builtin.c b/src/builtin.c index 4eaccc6..988cc93 100644 --- a/src/builtin.c +++ b/src/builtin.c @@ -1,6 +1,6 @@ /* GNU m4 -- A simple macro processor - Copyright (C) 1989-1994, 2000, 2004, 2006-2014, 2016-2017 Free + Copyright (C) 1989-1994, 2000, 2004, 2006-2014, 2016-2017, 2020 Free Software Foundation, Inc. This file is part of GNU M4. @@ -449,8 +449,9 @@ numeric_arg (token_data *macro, const char *arg, int *valuep) /* Digits for number to ASCII conversions. */ static char const digits[] = "0123456789abcdefghijklmnopqrstuvwxyz"; +/* The 'volatile' neutralizes a clang 6.0.1 optimization bug. */ const char * -ntoa (int32_t value, int radix) +ntoa (int32_t volatile value, int radix) { bool negative; uint32_t uvalue; -- 2.7.4