[Bug c++/114772] New: pragma GCC target applied to earlier template function with __attribute__((warn_unused_result))

[Bug c++/114772] New: pragma GCC target applied to earlier template function with __attribute__((warn_unused_result))

[mjires at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114772

            Bug ID: 114772
           Summary: pragma GCC target applied to earlier template function
                    with __attribute__((warn_unused_result))
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mjires at gcc dot gnu.org
                CC: jamborm at gcc dot gnu.org
  Target Milestone: ---

Following minimized testcase fails depending on warn_unused_result attribute.
Fails at least since GCC 10.

$ cat simdjson.cpp
template<typename V, bool STREAMING>
inline __attribute__((always_inline))
#ifdef FAIL
__attribute__((warn_unused_result))
#endif
int walk_document(V visitor) {return 0;}

template<bool STREAMING>
void parse_document() {
    int r = walk_document<bool, STREAMING>(false);
}

void stage2_next() {
    parse_document<true>();
}

#pragma GCC target("pclmul")



$ gcc simdjson.cpp -DFAIL
simdjson.cpp: In function ‘void parse_document() [with bool STREAMING = true]’:
simdjson.cpp:6:5: error: inlining failed in call to ‘always_inline’ ‘int
walk_document(V) [with V = bool; bool STREAMING = true]’: target specific
option mismatch
    6 | int walk_document(V visitor) {return 0;}
      |     ^~~~~~~~~~~~~
simdjson.cpp:10:43: note: called from here
   10 |     int r = walk_document<bool, STREAMING>(false);
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~



Without __attribute__((warn_unused_result)) it compiles without problems.

Inlining is denied in ix86_can_inline_p, because:
caller: void parse_document() [with bool STREAMING = true]/1
callee: int walk_document(V) [with V = bool; bool STREAMING = true]/2
caller_opts->x_ix86_isa_flags: 000c001100000012
callee_opts->x_ix86_isa_flags: 000c009100000012
So they differ by OPTION_MASK_ISA_PCLMUL

Source of this difference seems to be attribs.cc:decl_attributes, which is
called during template instantiation, but uses global_options.

[Bug c++/114772] pragma GCC target applied to earlier template function with __attribute__((warn_unused_result))

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114772

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=109753

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I suspect this and pr 109753 have the same underlying issue.

[Bug c++/114772] [13/14 Regression] pragma GCC target applied to earlier template function with __attribute__((warn_unused_result)) since r12-6904

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114772

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
                 CC|                            |jakub at gcc dot gnu.org
     Ever confirmed|0                           |1
   Target Milestone|---                         |13.3
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2024-04-19
            Summary|pragma GCC target applied   |[13/14 Regression] pragma
                   |to earlier template         |GCC target applied to
                   |function with               |earlier template function
                   |__attribute__((warn_unused_ |with
                   |result))                    |__attribute__((warn_unused_
                   |                            |result)) since r12-6904

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r12-6904-g66b86171188dcb61d2d0e0a4a98a7467e58a84a7

[Bug c++/114772] [13/14/15 Regression] pragma GCC target applied to earlier template function with __attribute__((warn_unused_result)) since r12-6904

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114772

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|13.3                        |13.4

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 13.3 is being released, retargeting bugs to GCC 13.4.