[PATCH, PR58066] preferred_stack_boundary update for tls expanded call

[Wei Mi]

> I tried pr58066-3.patch on the above testcase, the code it generated
> seems ok. I think after we change the 32bits pattern in i386.md to be
> similar as 64bits pattern, we should change 32bit expand to be similar
> as 64bit expand in legitimize_tls_address too?
>
> Thanks,
> Wei.
>

Sorry, I pasted the wrong code. This is the code generated by pr58066-3.patch.
wmi@miwei:/tmp$ cat 1.c
static __thread char ccc, bbb;

int __cxa_get_globals()
{
 return &ccc - &bbb;
}

wmi@miwei:/tmp$ ~/workarea/gcc-r208410-2/build/install/bin/gcc -O2
-fPIC -m32 -S 1.c
wmi@miwei:/tmp$ cat 1.s
        .file   "1.c"
        .section        .text.unlikely,"ax",@progbits
.LCOLDB0:
        .text
.LHOTB0:
        .p2align 4,,15
        .globl  __cxa_get_globals
        .type   __cxa_get_globals, @function
__cxa_get_globals:
.LFB0:
        .cfi_startproc
        pushl   %ebx
        .cfi_def_cfa_offset 8
        .cfi_offset 3, -8
        call    __x86.get_pc_thunk.bx
        addl    $_GLOBAL_OFFSET_TABLE_, %ebx
        subl    $8, %esp
        .cfi_def_cfa_offset 16
        leal    ccc@tlsldm(%ebx), %eax
        call    ___tls_get_addr@PLT
        addl    $8, %esp
        .cfi_def_cfa_offset 8
        leal    ccc@dtpoff(%eax), %edx
        leal    bbb@dtpoff(%eax), %eax
        popl    %ebx
        .cfi_restore 3
        .cfi_def_cfa_offset 4
        subl    %eax, %edx
        movl    %edx, %eax
        ret
        .cfi_endproc
.LFE0:
        .size   __cxa_get_globals, .-__cxa_get_globals
        .section        .text.unlikely
.LCOLDE0:
        .text
.LHOTE0:
        .section        .tbss,"awT",@nobits
        .type   bbb, @object
        .size   bbb, 1
bbb:
        .zero   1
        .type   ccc, @object
        .size   ccc, 1
ccc:
        .zero   1
        .section
.text.__x86.get_pc_thunk.bx,"axG",@progbits,__x86.get_pc_thunk.bx,comdat
        .globl  __x86.get_pc_thunk.bx
        .hidden __x86.get_pc_thunk.bx
        .type   __x86.get_pc_thunk.bx, @function
__x86.get_pc_thunk.bx:
.LFB1:
        .cfi_startproc
        movl    (%esp), %ebx
.LFB1:
        .cfi_startproc
        movl    (%esp), %ebx
        ret
        .cfi_endproc
.LFE1:
        .ident  "GCC: (GNU) 4.9.0 20140307 (experimental)"
        .section        .note.GNU-stack,"",@progbits