[Bug middle-end/50963] New: TLS incompatible with -mcmodel=large & PIC

[drepper.fsp at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50963

             Bug #: 50963
           Summary: TLS incompatible with -mcmodel=large & PIC
    Classification: Unclassified
           Product: gcc
           Version: 4.6.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: drepper.fsp@gmail.com


Due to some build problems with the default models a program was compiled with
-mcmodel=large.  But that seems to be incompatible with TLS in PIC.  This tiny
code sequence blows up gcc as recently as 4.6.2 (from Fedora rawhide):

__thread int a;

int f(int b)
{
  return a;
}


The ICE message when compiled with 'g++ -c -mcmodel=large t.c -fpic' is:

t.c: In function ‘int f(int)’:
t.c:6:1: error: unrecognizable insn:
(call_insn/u 6 5 7 3 (parallel [
            (set (reg:DI 0 ax)
                (call:DI (mem:QI (symbol_ref:DI ("__tls_get_addr")) [0 S1 A8])
                    (const_int 0 [0])))
            (unspec:DI [
                    (symbol_ref:DI ("a") [flags 0x10] <var_decl 0x7f55292c31e0
a>)
                ] UNSPEC_TLS_GD)
        ]) t.c:5 -1
     (expr_list:REG_EH_REGION (const_int -2147483648 [0xffffffff80000000])
        (nil))
    (nil))
t.c:6:1: internal compiler error: in extract_insn, at recog.c:2109