GCC Bugzilla Bug 24367

g++ -g -Wall -fPIC -O2 -funroll-loops -o /dev/null -c disk.cpp
disk.cpp: In function 'char* test(const char*, const char*)':
disk.cpp:13: error: unrecognizable insn:
(insn 542 541 544 26 (set (reg/f:SI 84)
        (plus:SI (reg:SI 12 %r12)
            (const:SI (plus:SI (unspec:SI [
                            (symbol_ref:SI ("_ZZ4testPKcS0_E8rtn_path") [flags
0x2] <var_decl 0x77db29a0 rtn_path>)
                        ] 112)
                    (const_int 1024 [0x400]))))) -1 (nil)
    (nil))
disk.cpp:13: internal compiler error: in extract_insn, at recog.c:2084

Code:
char *test(const char *parent, const char *child)
{
        static char rtn_path[1024];
        char *s = rtn_path;
        char *s_end = rtn_path + sizeof(rtn_path);
        const char *s2 = child;

        while( *s != '\0' )
                s++;
        while( (s < s_end) && (*s2 != '\0') )
                *s++ = *s2++;
        return(rtn_path);
}

A regression hunt using an s390-linux cross compiler on powerpc-linux, with the
submitter's testcase and options, identified this patch:

    http://gcc.gnu.org/viewcvs?view=rev&rev=88869

    r88869 | pinskia | 2004-10-11 03:42:09 +0000 (Mon, 11 Oct 2004)

My patch just exposed a latent bug as it does nothing that was not already done
before RTH removed the folding.

*** Bug 28717 has been marked as a duplicate of this bug. ***

Happens on mainline as well.

This was a P2 before the new Priority system came into effect so moving it to a
P3.

Subject: Bug 24367

Author: krebbel
Date: Thu Aug 31 07:43:36 2006
New Revision: 116599

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=116599
Log:
2006-08-31  Andreas Krebbel  <krebbel1@de.ibm.com>

        PR target/24367
        * config/s390/s390.md ("movsi", "movdi" expander): Accept rtxes like
        r12 + SYMBOLIC_CONST.

2006-08-31  Andreas Krebbel  <krebbel1@de.ibm.com>

        PR target/24367
        * gcc.dg/pr24367.c: New testcase.


Added:
    trunk/gcc/testsuite/gcc.dg/pr24367.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/s390/s390.md
    trunk/gcc/testsuite/ChangeLog

Subject: Bug 24367

Author: krebbel
Date: Thu Aug 31 07:50:19 2006
New Revision: 116600

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=116600
Log:
2006-08-31  Andreas Krebbel  <krebbel1@de.ibm.com>

        PR target/24367
        * config/s390/s390.md ("movsi", "movdi" expander): Accept rtxes like
        r12 + SYMBOLIC_CONST.

2006-08-31  Andreas Krebbel  <krebbel1@de.ibm.com>

        PR target/24367
        * gcc.dg/pr24367.c: New testcase.


Added:
    branches/gcc-4_1-branch/gcc/testsuite/gcc.dg/pr24367.c
Modified:
    branches/gcc-4_1-branch/gcc/ChangeLog
    branches/gcc-4_1-branch/gcc/config/s390/s390.md
    branches/gcc-4_1-branch/gcc/testsuite/ChangeLog

Although the bug is latent in gcc 4.0 as well I've applied the patch to 4.1 and
4.2 only. I could not reproduce a failure with gcc 4.0 so I've left it as is
rather than risking new problems.