[Bug c/110737] New: GCC: internal compiler error: Segmentation fault when processing __builtin_isinf and _Atomic long double together

[Bug c/110737] New: GCC: internal compiler error: Segmentation fault when processing __builtin_isinf and _Atomic long double together

[141242068 at smail dot nju.edu.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110737

            Bug ID: 110737
           Summary: GCC: internal compiler error: Segmentation fault when
                    processing __builtin_isinf and _Atomic long double
                    together
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: 141242068 at smail dot nju.edu.cn
  Target Milestone: ---

When attempting to compile below program using gcc-14 with option `gcc-14
small.c`, gcc throws internal error.
```
_Atomic long double c;
void f(void);
void g(void) { __builtin_isinf(c /= f()); }
```

The output of gcc is pasted below:
```
<source>: In function 'g':
<source>:3:1: error: void value not ignored as it ought to be
    3 | void g(void) { __builtin_isinf(c /= f()); }
      | ^~~~
<source>:3:34: internal compiler error: Segmentation fault
    3 | void g(void) { __builtin_isinf(c /= f()); }
      |                                  ^~
0x21594ee internal_error(char const*, ...)
        ???:0
0xd6ec47 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ???:0
0xd7182a gimplify_stmt(tree_node**, gimple**)
        ???:0
0xd6f79b gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ???:0
0xd7182a gimplify_stmt(tree_node**, gimple**)
        ???:0
0xd6ec6a gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ???:0
0xd7182a gimplify_stmt(tree_node**, gimple**)
        ???:0
0xd6ec04 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ???:0
0xd7182a gimplify_stmt(tree_node**, gimple**)
        ???:0
0xd72cc3 gimplify_body(tree_node*, bool)
        ???:0
0xd7311f gimplify_function_tree(tree_node*)
        ???:0
0xbaffa7 cgraph_node::analyze()
        ???:0
0xbb3af1 symbol_table::finalize_compilation_unit()
        ???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
```

The above segment fault can be verified at compiler explorer:
https://gcc.godbolt.org/z/Ghxe5Mc6e

[Bug c/110737] GCC: internal compiler error: Segmentation fault when processing __builtin_isinf and _Atomic long double together

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110737

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2023-07-19
           Keywords|                            |error-recovery,
                   |                            |ice-on-invalid-code
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.

[Bug c/110737] GCC: internal compiler error: Segmentation fault when processing __builtin_isinf and _Atomic long double together

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110737

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
7137          /* TARGET_EXPR temps aren't part of the enclosing block, so add
it
7138             to the temps list.  Handle also variable length TARGET_EXPRs. 
*/
7139          if (!poly_int_tree_p (DECL_SIZE (temp)))
7140            {
7141              if (!TYPE_SIZES_GIMPLIFIED (TREE_TYPE (temp)))
7142                gimplify_type_sizes (TREE_TYPE (temp), &init_pre_p);
7143              /* FIXME: this is correct only when the size of the type does
(gdb) p temp
$1 = (tree) 0x7ffff760d3f0
(gdb) p debug_tree(temp)
 <var_decl 0x7ffff760d3f0 D.4640
    type <void_type 0x7ffff761e0a8 void VOID
        align:8 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x7ffff761e0a8
        pointer_to_this <pointer_type 0x7ffff761e150>>
    addressable used ignored read VOID t5.c:4:1

(slightly different compiler)
  TARGET_EXPR <D.2762, f ()>;
  TARGET_EXPR <D.2763, (void) (D.2763 = VIEW_CONVERT_EXPR<long
double>(__atomic_load_16 ((const volatile void *) &c, 5)))>;
  TARGET_EXPR <D.2768, __builtin_ia32_fnstenv ((void *) &D.2768)>;,
__builtin_ia32_fnclex ();;, TARGET_EXPR <D.2770, __builtin_ia32_stmxcsr ()>;,
TARGET_EXPR <D.2771, (D.2770 | 8064) & 4294967232>;;, __builtin_ia32_ldmxcsr
(D.2771);;

  if (__atomic_compare_exchange_16 ((volatile void *) &c, (void *) &D.2763,
VIEW_CONVERT_EXPR<__int128 unsigned>(D.2764), 0, 5, 5))


Note for C++ front-end, it uses error_mark_node for here rather than a void
type for D.2762 ( D.4640)

[Bug c/110737] GCC: internal compiler error: Segmentation fault when processing __builtin_isinf and _Atomic long double together

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110737

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |6.1.0, 8.1.0

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
In GCC 4.9-5.x, this just ICEd. Before GCC 4.9, GCC didn't recongize _Atomic.

[Bug c/110737] GCC: internal compiler error: Segmentation fault when processing __builtin_isinf and _Atomic long double together

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110737

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
You can also get ICE with _Atomic int with a similar testcase:
```
_Atomic int c;
void f(void);
int g(void)
{
        return (c += f());
}
```

[Bug c/110737] GCC: internal compiler error: Segmentation fault when processing __builtin_isinf and _Atomic long double together

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110737

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
build_atomic_assign does not handle this in a reasonable fashion.
Note there is code like :
  if (modifycode != NOP_EXPR)
    add_stmt (rhs);

  /* NOP_EXPR indicates it's a straight store of the RHS. Simply issue
     an atomic_store.  */
  if (modifycode == NOP_EXPR)
    {
...
      /* VAL is the value which was stored, return a COMPOUND_STMT of
         the statement and that value.  */
      return build2 (COMPOUND_EXPR, nonatomic_lhs_type, compound_stmt, val);
    }

Which definitely could be improved too.