[Bug tree-optimization/111036] New: Code generation error in handling __builtin_constant_p

[Bug tree-optimization/111036] New: Code generation error in handling __builtin_constant_p

[bmei at broadcom dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111036

            Bug ID: 111036
           Summary: Code generation error in handling __builtin_constant_p
           Product: gcc
           Version: 13.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bmei at broadcom dot com
  Target Milestone: ---

Compile and run following code


#include <stdio.h>
#define __align(n) __attribute__((aligned(n)))

__attribute__((aligned(32))) static struct {

    unsigned long long available_cmd_ids_per_core[2];
} _rl2c_cmd_id_data;

static inline void __attribute__((always_inline))
foo (void *base, size_t length)
{
    unsigned long int p = (unsigned long int) base;
    if (__builtin_constant_p(p) && (p & 31) == 0) { printf("constant p &&
aligned to 32\n"); } 
    else if (__builtin_constant_p(length)) { printf("constant length\n");} 
    else { printf("else\n"); }
}

int main(int argc, char **argv)
{
    foo(&_rl2c_cmd_id_data, sizeof(*(&_rl2c_cmd_id_data)));
    return 0;
}


With gcc 12.1.0 & gcc 13.1.0,  I got segmentation fault. With 11.1.0 and below,
I got correct result. I examined the dumped tree IR. In einline pass, a
__builtin_unreachable is inserted for else if/else branches as the compiler
probably thinks __builtin_constant_p(p) & (p&31) is always true. But the later
passes think __builtin_constant_p(p) is always false. Therefore all code are
optimized away.

[Bug ipa/111036] Code generation error in handling __builtin_constant_p

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111036

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |DUPLICATE
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=99309

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I suspect this is the same bug as PR 99309 just exposed slightly differently.

*** This bug has been marked as a duplicate of bug 99309 ***

[Bug ipa/111036] Code generation error in handling __builtin_constant_p

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111036

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|DUPLICATE                   |---

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Reopen as I didn't mean to mark it as a dup just yet.

[Bug ipa/111036] Code generation error in handling __builtin_constant_p

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111036

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |99309
      Known to work|                            |9.5.0
             Status|UNCONFIRMED                 |NEW
      Known to fail|                            |10.5.0, 11.1.0
   Last reconfirmed|                            |2023-08-20
     Ever confirmed|0                           |1

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99309
[Bug 99309] [11/12/13/14 Regression] Segmentation fault with
__builtin_constant_p usage at -O2