[Bug testsuite/113226] New: [14 Regression] testsuite/std/ranges/iota/max_size_type.cc fails for cris-elf after r14-6888-ga138b99646a555

[Bug testsuite/113226] New: [14 Regression] testsuite/std/ranges/iota/max_size_type.cc fails for cris-elf after r14-6888-ga138b99646a555

[hp at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113226

            Bug ID: 113226
           Summary: [14 Regression]
                    testsuite/std/ranges/iota/max_size_type.cc fails for
                    cris-elf after r14-6888-ga138b99646a555
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: testsuite
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hp at gcc dot gnu.org
  Target Milestone: ---

After r14-6888-ga138b99646a555, I see, for cris-elf (32-bit target, no 128bit):
FAIL: std/ranges/iota/max_size_type.cc  -std=gnu++20 execution test
FAIL: std/ranges/iota/max_size_type.cc  -std=gnu++26 execution test

And in the .log:

spawn cris-elf-run ./max_size_type.exe^
Inconsistency found: 1 0 -100 -100^
/x/gcc/libstdc++-v3/testsuite/std/ranges/iota/max_size_type.cc:246: void
test02() [with bool signed_p = true; bool shorten_p = false]: Assertion '0'
failed.
program stopped with signal 6 (Aborted).
FAIL: std/ranges/iota/max_size_type.cc  -std=gnu++20 execution test

Changing all s/ok &=/VERIFY/ (plus adding one level of parentheses to one of
the lines) show:

/x/gcc/libstdc++-v3/testsuite/std/ranges/iota/max_size_type.cc:217: void
test02() [with bool signed_p = true; bool shorten_p = false]: Assertion 'i*j ==
shorten_type(max_type(i)*j)' failed.
program stopped with signal 6 (Aborted).

Further instrumentation, adding among other lines:
```
          if (signed_p && ! shorten_p)
            std::cerr << "j == " << int64_t(j) << std::endl;
          if (!(i*j == shorten_type(max_type(i)*j)))
            {
              std::cerr << "i == " << int64_t(i) << ", j == " << j << ", i*j ==
" << int64_t(i*j) << ", max_type(i) == \
" << int64_t(max_type(i));
              std::cerr << ", max_type(i)*j == " << int64_t(max_type(i)*j) <<
std::endl;
            }
''' 

shows that this is (see above for template parameters):
i == 1, j == -100, i*j == 4294967196, max_type(i) == 1, max_type(i)*j == -100

and that large number is as you might guess, (unsigned) -100.

Not sure if this is a bug in the testcase or elsewhere, but I'll start my
guessing with testsuite.

[Bug testsuite/113226] [14 Regression] testsuite/std/ranges/iota/max_size_type.cc fails for cris-elf after r14-6888-ga138b99646a555

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113226

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ppalka at gcc dot gnu.org

--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Huh, how bizarre.

> i == 1, j == -100, i*j == 4294967196, max_type(i) == 1, max_type(i)*j == -100

Here i and j are just ordinary 'long long', so I don't get why i*j is
4294967196 instead of -100?

[Bug testsuite/113226] [14 Regression] testsuite/std/ranges/iota/max_size_type.cc fails for cris-elf after r14-6888-ga138b99646a555

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113226

--- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> ---
(In reply to Patrick Palka from comment #1)
> Huh, how bizarre.
> 
> > i == 1, j == -100, i*j == 4294967196, max_type(i) == 1, max_type(i)*j == -100
> 
> Here i and j are just ordinary 'long long', so I don't get why i*j is
> 4294967196 instead of -100?

Everything else, in particular that int64_t(max_type(i)*j) is -100, seems
correct/expected to me.  FWIW that expression computes the product of the
corresponding promoted/sign-extended 65-bit precision values, and the overall
check is analogous to

  int32_t i = 1, j = -100;
  assert (int64_t(i*j) == int64_t(i)*j);

except the two precisions are 64/65 bits instead of 32/64 bits.

(When shorten_p is true, the overall check is analogous to
 assert (i*j == int32_t(int64_t(i)*j)) instead.)

[Bug testsuite/113226] [14 Regression] testsuite/std/ranges/iota/max_size_type.cc fails for cris-elf after r14-6888-ga138b99646a555

[hp at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113226

--- Comment #3 from Hans-Peter Nilsson <hp at gcc dot gnu.org> ---
(In reply to Patrick Palka from comment #1)
> Huh, how bizarre.

Indeed.  I'm *not* ruling out an actual gcc bug.  Whether in the target or
middle-end this time I dare not guess; too few posts.

JFTR; I already mentioned this in the gcc-patches post: I see only posts on
gcc-testresults@ that include r14-6888-ga138b99646a555 for 64-bit-targets with
"-m32" multilibs, and I don't trust them to treat that hw_type the same.

[Bug testsuite/113226] [14 Regression] testsuite/std/ranges/iota/max_size_type.cc fails for cris-elf after r14-6888-ga138b99646a555

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113226

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0

[Bug target/113226] [14 Regression] testsuite/std/ranges/iota/max_size_type.cc fails for cris-elf after r14-6888-ga138b99646a555

[hp at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113226

Hans-Peter Nilsson <hp at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|testsuite                   |target

--- Comment #4 from Hans-Peter Nilsson <hp at gcc dot gnu.org> ---
(In reply to Hans-Peter Nilsson from comment #3)
> (In reply to Patrick Palka from comment #1)
> > Huh, how bizarre.
> 
> Indeed.  I'm *not* ruling out an actual gcc bug.  Whether in the target or
> middle-end this time I dare not guess; too few posts.

I don't see this FAIL for m68k-unknown-linux-gnu in
https://gcc.gnu.org/pipermail/gcc-testresults/2024-January/804595.html so let's
change to target component.

I'll see if I can revive one of the other *-elf toolchains to the point where
the libstdc++-v3 tests are useful before digging in.  (But also subject to
other priorities and unfortunately not among the highest.)

[Bug target/113226] [14 Regression] testsuite/std/ranges/iota/max_size_type.cc fails for cris-elf after r14-6888-ga138b99646a555

[law at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113226

Jeffrey A. Law <law at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at gcc dot gnu.org
           Priority|P3                          |P4

[Bug target/113226] [14/15 Regression] testsuite/std/ranges/iota/max_size_type.cc fails for cris-elf after r14-6888-ga138b99646a555

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113226

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|14.0                        |14.2

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 14.1 is being released, retargeting bugs to GCC 14.2.