[Bug c++/118114] std::call_once crashes on LoongArch when program is built with -fPIC -mtls-dialect=desc

[xry111 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118114

--- Comment #3 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
Hmm...  This seems like a ld bug:

a.out:     file format elf64-loongarch

DYNAMIC RELOCATION RECORDS
OFFSET           TYPE              VALUE
0000000000007d90 R_LARCH_RELATIVE  *ABS*+0x0000000000000d88
0000000000007d98 R_LARCH_RELATIVE  *ABS*+0x0000000000000d30
0000000000007fa8 R_LARCH_RELATIVE  *ABS*+0x0000000000000e50
0000000000008060 R_LARCH_RELATIVE  *ABS*+0x0000000000008060
0000000000000000 R_LARCH_NONE      *ABS*
0000000000000000 R_LARCH_NONE      *ABS*
0000000000000000 R_LARCH_NONE      *ABS*
0000000000007fa0 R_LARCH_TLS_TPREL64  _ZSt15__once_callable@GLIBCXX_3.4.11
0000000000007fc0 R_LARCH_TLS_TPREL64  _ZSt11__once_call@GLIBCXX_3.4.11

... ...

So it's doing a desc => IE relaxation.  But the code sequence isn't changed and
still expects TLS desc:

0000000000000e58
<_ZZNSt9once_flag18_Prepare_executionC4IZSt9call_onceIRFvvEJEEvRS_OT_DpOT0_EUlvE_EERS6_ENUlvE_4_FUNEv>:
 e58:   02ffc063        addi.d          $sp, $sp, -16
 e5c:   29c02061        st.d            $ra, $sp, 8
 e60:   1a000104        pcalau12i       $a0, 8
 e64:   02fe8084        addi.d          $a0, $a0, -96
 e68:   28c00081        ld.d            $ra, $a0, 0
 e6c:   4c000021        jirl            $ra, $ra, 0