Re: [PATCH] testsuite: Fix c-c++-common/pr103798-2.c on Solaris [PR113706]

[Rainer Orth]

Hi Jason,

> On 2/2/24 10:23, Rainer Orth wrote:
>> c-c++-common/pr103798-2.c FAILs on Solaris when compiled as C++:
>> FAIL: c-c++-common/pr103798-2.c  -std=gnu++14  scan-assembler-not memchr
>> FAIL: c-c++-common/pr103798-2.c  -std=gnu++17  scan-assembler-not memchr
>> FAIL: c-c++-common/pr103798-2.c  -std=gnu++20  scan-assembler-not memchr
>> FAIL: c-c++-common/pr103798-2.c  -std=gnu++98  scan-assembler-not memchr
>> As H.J. analyzed in the PR, Solaris <string.h> declares std::memchr, not
>> memchr, which isn't treated as __builtin_memchr.
>
> The problem seems to be not the std::, but that the Solaris string.h
> declares
>
> const void *memchr(const void *, int, size_t);
>
> as specified by the C++ standard, while gcc expects the return type to be
> void* like in C.
>
> This looks like a GCC bug, not Solaris; I'd prefer to xfail the testcase
> rather than work around the compiler bug.

thanks for the analysis.

What I found with my current patch, just the memchr prototype changed to
always return const void *, the test still PASSes as C, but FAILs as
C++.

In the C++ case I get a warning:

/vol/gcc/src/hg/master/local/gcc/testsuite/c-c++-common/pr103798-2.c:10:20: 
warning: declaration of ‘const void* memchr(const void*, int, size_t)’ 
conflicts with built-in declaration ‘void* memchr(const void*, int, unsigned 
int)’ [-Wbuiltin-declaration-mismatch]

Here's the patch to xfail the test instead.

Tested on sparc-sun-solaris2.11 and x86_64-pc-linux-gnu.

Ok for trunk?

        Rainer

-- 
-----------------------------------------------------------------------------
Rainer Orth, Center for Biotechnology, Bielefeld University


2024-02-12  Rainer Orth  <r...@cebitec.uni-bielefeld.de>

        testsuite:
        PR tree-optimization/113706
        * c-c++-common/pr103798-2.c (scan-assembler-not): xfail for C++ on
        Solaris.



# HG changeset patch
# Parent  1409f56e818a7240dd65da9566400f308a996beb
testsuite: Fix c-c++-common/pr103798-2.c on Solaris [PR113706]

diff --git a/gcc/testsuite/c-c++-common/pr103798-2.c b/gcc/testsuite/c-c++-common/pr103798-2.c
--- a/gcc/testsuite/c-c++-common/pr103798-2.c
+++ b/gcc/testsuite/c-c++-common/pr103798-2.c
@@ -27,4 +27,5 @@ main ()
  return 0;
 }
 
-/* { dg-final { scan-assembler-not "memchr" } } */
+/* See PR tree-optimization/113706 for the xfail.  */
+/* { dg-final { scan-assembler-not "memchr" { xfail { c++ && *-*-solaris2* } } } } */