[Bug target/68937] i686: -fno-plt produces wrong code (maybe only with tailcall)

["zsojka at seznam dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68937

--- Comment #9 from Zdenek Sojka <zsojka at seznam dot cz> ---
(In reply to H.J. Lu from comment #8)
> Created attachment 37054 [details]
> A patch
> 
> I am testing this.

It introduces ICE in cselib_invalidate_regno with -fPIC -fno-plt, for example:

$ gcc -O2 -funroll-loops -fPIC -fno-plt
gcc/testsuite/gcc.c-torture/compile/20080419-1.c
gcc/testsuite/gcc.c-torture/compile/20080419-1.c: In function
'dmi_scan_machine':
gcc/testsuite/gcc.c-torture/compile/20080419-1.c:6:1: internal compiler error:
in cselib_invalidate_regno, at cselib.c:2148
 }
 ^

0x755f38 cselib_invalidate_regno
        /repo/gcc-trunk/gcc/cselib.c:2147
0xafeaa9 note_stores(rtx_def const*, void (*)(rtx_def*, rtx_def const*, void*),
void*)
        /repo/gcc-trunk/gcc/rtlanal.c:1865
0x75d499 cselib_record_sets
        /repo/gcc-trunk/gcc/cselib.c:2567
0x75e5d9 cselib_process_insn(rtx_insn*)
        /repo/gcc-trunk/gcc/cselib.c:2674
0xa86566 reload_cse_regs_1
        /repo/gcc-trunk/gcc/postreload.c:221
0xa86c9d reload_cse_regs
        /repo/gcc-trunk/gcc/postreload.c:67
0xa86c9d execute
        /repo/gcc-trunk/gcc/postreload.c:2336