[Bug target/21657] New: [4.0 regression] TLS reference miscompiled

["schwab at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>]

The patch from PR21412 is causing miscompilation of glibc.  Anything that uses  
libpthread is crashing in __libc_dl_error_tsd. 
 
void ** __attribute__ ((const)) 
__libc_dl_error_tsd (void) 
{ 
  static __thread void *data; 
  return &data; 
} 
 
When compiled without the patch: 
 
dl-tsd.os:     file format elf64-ia64-little 
 
Disassembly of section .text: 
 
0000000000000000 <__libc_dl_error_tsd>: 
   0:   18 08 15 06 80 05       [MMB]       alloc r33=ar.pfs,5,3,0 
                        1: LTOFF_DTPMOD22       data.6704 
   6:   e0 00 04 00 48 00                   addl r14=0,r1 
   c:   00 00 00 20                         nop.b 0x0 
  10:   01 10 01 02 00 21       [MII]       mov r34=r1 
  16:   00 02 00 62 00 80                   mov r32=b0 
  1c:   04 00 00 84                         mov r36=r0;; 
  20:   1d 18 01 1c 18 10       [MFB]       ld8 r35=[r14] 
                        22: PCREL21B    __tls_get_addr 
  26:   00 00 00 02 00 00                   nop.f 0x0 
  2c:   08 00 00 50                         br.call.sptk.many b0=20 
<__libc_dl_error_tsd+0x20>;; 
  30:   08 08 00 44 00 21       [MMI]       mov r1=r34 
  36:   20 00 20 00 42 00                   mov r2=r8 
  3c:   00 0a 00 07                         mov b0=r32 
  40:   0b 00 00 00 01 00       [MMI]       nop.m 0x0;; 
                        41: DTPREL22    data.6704 
  46:   20 00 08 00 48 00                   addl r2=0,r2 
  4c:   10 02 aa 00                         mov.i ar.pfs=r33;; 
  50:   11 00 00 00 01 00       [MIB]       nop.m 0x0 
  56:   80 00 08 00 42 80                   mov r8=r2 
  5c:   08 00 84 00                         br.ret.sptk.many b0;; 
 
 
When compiled with the patch: 
 
dl-tsd.os:     file format elf64-ia64-little 
 
Disassembly of section .text: 
 
0000000000000000 <__libc_dl_error_tsd>: 
   0:   08 08 15 06 80 05       [MMI]       alloc r33=ar.pfs,5,3,0 
                        1: LTOFF_DTPMOD22       data.6704 
   6:   e0 00 04 00 48 00                   addl r14=0,r1 
   c:   04 00 c4 00                         mov r32=b0 
  10:   0b 10 01 02 00 21       [MMI]       mov r34=r1;; 
  16:   e0 00 38 30 20 80                   ld8 r14=[r14] 
  1c:   04 00 00 84                         mov r36=r0;; 
  20:   1d 18 01 1c 18 10       [MFB]       ld8 r35=[r14] 
                        22: PCREL21B    __tls_get_addr 
  26:   00 00 00 02 00 00                   nop.f 0x0 
  2c:   08 00 00 50                         br.call.sptk.many b0=20 
<__libc_dl_error_tsd+0x20>;; 
  30:   09 08 00 44 00 21       [MMI]       mov r1=r34 
  36:   20 00 20 00 42 00                   mov r2=r8 
  3c:   00 0a 00 07                         mov b0=r32;; 
  40:   11 40 00 04 00 24       [MIB]       addl r8=0,r2 
                        40: DTPREL22    data.6704 
  46:   00 08 01 55 00 80                   mov.i ar.pfs=r33 
  4c:   08 00 84 00                         br.ret.sptk.many b0;; 
 
The bad version has one indirection on r14 too much.

-- 
           Summary: [4.0 regression] TLS reference miscompiled
           Product: gcc
           Version: 4.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: schwab at suse dot de
                CC: gcc-bugs at gcc dot gnu dot org,rth at gcc dot gnu dot
                    org
GCC target triplet: ia64-linux
OtherBugsDependingO 21412
             nThis:


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21657