[Bug middle-end/114136] New: wrong code for c23 fully anonymous arg lists on arm

[Bug middle-end/114136] New: wrong code for c23 fully anonymous arg lists on arm

[rearnsha at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114136

            Bug ID: 114136
           Summary: wrong code for c23 fully anonymous arg lists on arm
           Product: gcc
           Version: 13.1.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rearnsha at gcc dot gnu.org
  Target Milestone: ---
            Target: arm

On arm, a fully anonymous c23-style function is called incorrectly.  All
arguments are passed on the stack while the receiving function expects r0-r3 to
be used for the initial arguments.

For example,

void f (...);

void g()
{
    f (1, 2, 3, 4);
}

With gcc compiles to:

g:
        push    {lr}
        movs    r0, #1
        movs    r1, #2
        sub     sp, sp, #20
        movs    r2, #3
        movs    r3, #4
        stm     sp, {r0, r1, r2, r3}  // Arguments pushed to stack (wrong)
        bl      f
        add     sp, sp, #20
        ldr     pc, [sp], #4

When the correct code (eg, as produced by clang) is something like

g:
        mov     r0, #1
        mov     r1, #2
        mov     r2, #3
        mov     r3, #4
        b       f

compile with, eg 

arm-non-eabi-gcc -O2 -c23

[Bug middle-end/114136] wrong code for c23 fully anonymous arg lists on arm

[rearnsha at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114136

Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-02-27

[Bug middle-end/114136] wrong code for c23 fully anonymous arg lists on arm

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114136

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |testsuite-fail

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The following testcases fail because of this:

FAIL: gcc.dg/c23-stdarg-4.c execution test
FAIL: gcc.dg/torture/c23-stdarg-split-1a.c   -O0  execution test
FAIL: gcc.dg/torture/c23-stdarg-split-1a.c   -O1  execution test
FAIL: gcc.dg/torture/c23-stdarg-split-1a.c   -O2  execution test
FAIL: gcc.dg/torture/c23-stdarg-split-1a.c   -O2 -flto -fno-use-linker-plugin
-flto-partition=none  execution test
FAIL: gcc.dg/torture/c23-stdarg-split-1a.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  execution test
FAIL: gcc.dg/torture/c23-stdarg-split-1a.c   -O3 -g  execution test
FAIL: gcc.dg/torture/c23-stdarg-split-1a.c   -Os  execution test

[Bug middle-end/114136] wrong code for c23 fully anonymous arg lists on arm

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114136

--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:b5377928a2a5cd2a79eda59e2eba7d0511bf7566

commit r14-9255-gb5377928a2a5cd2a79eda59e2eba7d0511bf7566
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Mar 1 15:42:52 2024 +0100

    calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR114136]

    On Tue, Feb 27, 2024 at 04:41:32PM +0000, Richard Earnshaw wrote:
    > On Arm the PR107453 change is causing all anonymous arguments to be
passed on the
    > stack, which is incorrect per the ABI.  On a target that uses
    > 'pretend_outgoing_vararg_named', why is it correct to set n_named_args to
    > zero?  Is it enough to guard both the statements you've added with
    > !targetm.calls.pretend_outgoing_args_named?

    The TYPE_NO_NAMED_ARGS_STDARG_P functions (C23 fns like void foo (...) {})
    have NULL type_arg_types, so the list_length (type_arg_types) isn't done
for
    it, but it should be handled as if it was non-NULL but list length was 0.

    So, for the
      if (type_arg_types != 0)
        n_named_args
          = (list_length (type_arg_types)
             /* Count the struct value address, if it is passed as a parm.  */
             + structure_value_addr_parm);
      else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
        n_named_args = 0;
      else
        /* If we know nothing, treat all args as named.  */
        n_named_args = num_actuals;
    case, I think guarding it by any target hooks is wrong, although
    I guess it should have been
        n_named_args = structure_value_addr_parm;
    instead of
        n_named_args = 0;

    For the second
      if (type_arg_types != 0
          && targetm.calls.strict_argument_naming (args_so_far))
        ;
      else if (type_arg_types != 0
               && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far))
        /* Don't include the last named arg.  */
        --n_named_args;
      else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
        n_named_args = 0;
      else
        /* Treat all args as named.  */
        n_named_args = num_actuals;
    I think we should treat those as if type_arg_types was non-NULL
    with 0 elements in the list, except the --n_named_args would for
    !structure_value_addr_parm lead to n_named_args = -1, I think we want
    0 for that case.

    2024-03-01  Jakub Jelinek  <jakub@redhat.com>

            PR middle-end/114136
            * calls.cc (expand_call): For TYPE_NO_NAMED_ARGS_STDARG_P set
            n_named_args initially before INIT_CUMULATIVE_ARGS to
            structure_value_addr_parm rather than 0, after it don't modify
            it if strict_argument_naming and clear only if
            !pretend_outgoing_varargs_named.

[Bug middle-end/114136] wrong code for c23 fully anonymous arg lists on arm

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114136

--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:96e6576a1ba0080e70fef4a6f9cc3129fcf6f008

commit r13-8397-g96e6576a1ba0080e70fef4a6f9cc3129fcf6f008
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Mar 1 15:42:52 2024 +0100

    calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR114136]

    On Tue, Feb 27, 2024 at 04:41:32PM +0000, Richard Earnshaw wrote:
    > On Arm the PR107453 change is causing all anonymous arguments to be
passed on the
    > stack, which is incorrect per the ABI.  On a target that uses
    > 'pretend_outgoing_vararg_named', why is it correct to set n_named_args to
    > zero?  Is it enough to guard both the statements you've added with
    > !targetm.calls.pretend_outgoing_args_named?

    The TYPE_NO_NAMED_ARGS_STDARG_P functions (C23 fns like void foo (...) {})
    have NULL type_arg_types, so the list_length (type_arg_types) isn't done
for
    it, but it should be handled as if it was non-NULL but list length was 0.

    So, for the
      if (type_arg_types != 0)
        n_named_args
          = (list_length (type_arg_types)
             /* Count the struct value address, if it is passed as a parm.  */
             + structure_value_addr_parm);
      else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
        n_named_args = 0;
      else
        /* If we know nothing, treat all args as named.  */
        n_named_args = num_actuals;
    case, I think guarding it by any target hooks is wrong, although
    I guess it should have been
        n_named_args = structure_value_addr_parm;
    instead of
        n_named_args = 0;

    For the second
      if (type_arg_types != 0
          && targetm.calls.strict_argument_naming (args_so_far))
        ;
      else if (type_arg_types != 0
               && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far))
        /* Don't include the last named arg.  */
        --n_named_args;
      else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
        n_named_args = 0;
      else
        /* Treat all args as named.  */
        n_named_args = num_actuals;
    I think we should treat those as if type_arg_types was non-NULL
    with 0 elements in the list, except the --n_named_args would for
    !structure_value_addr_parm lead to n_named_args = -1, I think we want
    0 for that case.

    2024-03-01  Jakub Jelinek  <jakub@redhat.com>

            PR middle-end/114136
            * calls.cc (expand_call): For TYPE_NO_NAMED_ARGS_STDARG_P set
            n_named_args initially before INIT_CUMULATIVE_ARGS to
            structure_value_addr_parm rather than 0, after it don't modify
            it if strict_argument_naming and clear only if
            !pretend_outgoing_varargs_named.

    (cherry picked from commit b5377928a2a5cd2a79eda59e2eba7d0511bf7566)

[Bug middle-end/114136] wrong code for c23 fully anonymous arg lists on arm

[rearnsha at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114136

Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
   Target Milestone|---                         |13.3
         Resolution|---                         |FIXED

--- Comment #4 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
fixed