[Bug target/47909] New: referring to __thread var with -fpic -O0 ICEs final_scan_insn on m68k-linux

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47909

           Summary: referring to __thread var with -fpic -O0 ICEs
                    final_scan_insn on m68k-linux
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mikpe@it.uu.se


> cat /tmp/pie-1.c
__thread int a;
int main(void) { return a; }
> /tmp/objdir46/gcc/xgcc -B/tmp/objdir46/gcc/ -O0 -fpic -S /tmp/pie-1.c
/tmp/pie-1.c: In function 'main':
/tmp/pie-1.c:2:1: error: insn does not satisfy its constraints:
(insn 22 2 5 (set (reg:SI 0 %d0 [33])
        (const:SI (unspec:SI [
                    (symbol_ref:SI ("a") [flags 0x10] <var_decl 0xb75c8f60 a>)
                    (const_int 1 [0x1])
                ] 6))) /tmp/pie-1.c:2 36 {*movsi_m68k}
     (nil))
/tmp/pie-1.c:2:1: internal compiler error: in final_scan_insn, at final.c:2579
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Same result with -fPIC or -fpie.  Goes away with -O1 or higher.

This bug causes gcc.dg/tls/pie-1.c to fail with gcc-4.5.2 and gcc-4.6.0.
Doesn't ICE gcc-4.4.5, but there it uses emutls (4.5 added NPTL support).

binutils-2.20.1, glibc-2.11.2 w/ NPTL backported.

> /tmp/objdir46/gcc/xgcc -v
Using built-in specs.
COLLECT_GCC=/tmp/objdir46/gcc/xgcc
Target: m68k-unknown-linux
Configured with: /tmp/gcc-4.6-20110219/configure --target=m68k-unknown-linux
--prefix=/home/mikpe/pkgs/linux-x86/cross-m68k
--with-gmp=/home/mikpe/pkgs/linux-x86/gmp-4.3.2
--with-mpfr=/home/mikpe/pkgs/linux-x86/mpfr-2.4.2
--with-mpc=/home/mikpe/pkgs/linux-x86/mpc-0.8.2 --disable-plugin --disable-lto
--disable-nls --enable-shared --disable-libmudflap --disable-multilib
--enable-threads=posix --enable-checking=release --enable-languages=c
Thread model: posix
gcc version 4.6.0 20110219 (experimental) (GCC)