[Bug target/112578] New: LoongArch: Wrong code -with -mlsx -fno-fp-int-builtin-inexact

[Bug target/112578] New: LoongArch: Wrong code -with -mlsx -fno-fp-int-builtin-inexact

[xry111 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112578

            Bug ID: 112578
           Summary: LoongArch: Wrong code -with -mlsx
                    -fno-fp-int-builtin-inexact
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: xry111 at gcc dot gnu.org
  Target Milestone: ---

$ cat t.c
#include <assert.h>
#include <fenv.h>

float f[4] = { 11.4, 5.14, 19.19, 8.10 };

int main()
{
  for (int i = 0; i < 4; i++)
    f[i] = __builtin_floorf (f[i]);

  assert (!fetestexcept (FE_INEXACT));
}
$ cc t.c -O2 -lm -fno-fp-int-builtin-inexact -mlsx
$ ./a.out
a.out: t.c:11: main: Assertion `!fetestexcept (FE_INEXACT)' failed.
Aborted (core dumped)

[Bug target/112578] LoongArch: Wrong code -with -mlsx -fno-fp-int-builtin-inexact

[xry111 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112578

Xi Ruoyao <xry111 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-11-17
           See Also|                            |https://github.com/loongson
                   |                            |-community/discussions/issu
                   |                            |es/7
           Keywords|                            |wrong-code
     Ever confirmed|0                           |1
           Assignee|unassigned at gcc dot gnu.org      |xry111 at gcc dot gnu.org
             Status|UNCONFIRMED                 |ASSIGNED

--- Comment #1 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
I've made a patch and it's under testing.

I've seen some "random" gcc.dg/torture/builtin-fp-int-inexact.c failures
recently but maybe it's not related, we don't enable LSX/LASX compiling it
anyway...  But who knows.

[Bug target/112578] LoongArch: Wrong code -with -mlsx -fno-fp-int-builtin-inexact

[chenglulu at loongson dot cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112578

--- Comment #2 from chenglulu <chenglulu at loongson dot cn> ---
(In reply to Xi Ruoyao from comment #1)
> I've made a patch and it's under testing.
> 
> I've seen some "random" gcc.dg/torture/builtin-fp-int-inexact.c failures
> recently but maybe it's not related, we don't enable LSX/LASX compiling it
> anyway...  But who knows.

This problem of random errors has always existed．This is a known problem．

[Bug target/112578] LoongArch: Wrong code -with -mlsx -fno-fp-int-builtin-inexact

[xry111 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112578

Xi Ruoyao <xry111 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|                            |https://gcc.gnu.org/piperma
                   |                            |il/gcc-patches/2023-Novembe
                   |                            |r/637097.html
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=107723
           Keywords|                            |patch

--- Comment #3 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
https://gcc.gnu.org/pipermail/gcc-patches/2023-November/637097.html

This fixes most of -ml[a]sx -fno-fp-int-builtin-inexact issues on LoongArch,
except PR107723.

[Bug target/112578] LoongArch: Wrong code -with -mlsx -fno-fp-int-builtin-inexact

[xry111 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112578

Xi Ruoyao <xry111 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|https://gcc.gnu.org/piperma |https://gcc.gnu.org/piperma
                   |il/gcc-patches/2023-Novembe |il/gcc-patches/2023-Novembe
                   |r/637097.html               |r/637316.html
           See Also|https://github.com/loongson |
                   |-community/discussions/issu |
                   |es/7                        |

--- Comment #4 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
(In reply to Xi Ruoyao from comment #3)
> https://gcc.gnu.org/pipermail/gcc-patches/2023-November/637097.html
> 
> This fixes most of -ml[a]sx -fno-fp-int-builtin-inexact issues on LoongArch,
> except PR107723.

Updated: https://gcc.gnu.org/pipermail/gcc-patches/2023-November/637316.html

[Bug target/112578] LoongArch: Wrong code -with -mlsx -fno-fp-int-builtin-inexact

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112578

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Xi Ruoyao <xry111@gcc.gnu.org>:

https://gcc.gnu.org/g:530348c418d9ec28aac5b151c15405bfb860e5c4

commit r14-5950-g530348c418d9ec28aac5b151c15405bfb860e5c4
Author: Xi Ruoyao <xry111@xry111.site>
Date:   Sat Nov 18 04:48:20 2023 +0800

    LoongArch: Fix usage of LSX and LASX frint/ftint instructions [PR112578]

    The usage LSX and LASX frint/ftint instructions had some problems:

    1. These instructions raises FE_INEXACT, which is not allowed with
       -fno-fp-int-builtin-inexact for most C2x section F.10.6 functions
       (the only exceptions are rint, lrint, and llrint).
    2. The "frint" instruction without explicit rounding mode is used for
       roundM2, this is incorrect because roundM2 is defined "rounding
       operand 1 to the *nearest* integer, rounding away from zero in the
       event of a tie".  We actually don't have such an instruction.  Our
       frintrne instruction is roundevenM2 (unfortunately, this is not
       documented).
    3. These define_insn's are written in a way not so easy to hack.

    So I removed these instructions and created a "simd.md" file, then added
    them and the corresponding expanders there.  The advantage of the
    simd.md file is we don't need to duplicate the RTL template twice (in
    lsx.md and lasx.md).

    gcc/ChangeLog:

            PR target/112578
            * config/loongarch/lsx.md (UNSPEC_LSX_VFTINT_S,
            UNSPEC_LSX_VFTINTRNE, UNSPEC_LSX_VFTINTRP,
            UNSPEC_LSX_VFTINTRM, UNSPEC_LSX_VFRINTRNE_S,
            UNSPEC_LSX_VFRINTRNE_D, UNSPEC_LSX_VFRINTRZ_S,
            UNSPEC_LSX_VFRINTRZ_D, UNSPEC_LSX_VFRINTRP_S,
            UNSPEC_LSX_VFRINTRP_D, UNSPEC_LSX_VFRINTRM_S,
            UNSPEC_LSX_VFRINTRM_D): Remove.
            (ILSX, FLSX): Move into ...
            (VIMODE): Move into ...
            (FRINT_S, FRINT_D): Remove.
            (frint_pattern_s, frint_pattern_d, frint_suffix): Remove.
            (lsx_vfrint_<flsxfmt>, lsx_vftint_s_<ilsxfmt>_<flsxfmt>,
            lsx_vftintrne_w_s, lsx_vftintrne_l_d, lsx_vftintrp_w_s,
            lsx_vftintrp_l_d, lsx_vftintrm_w_s, lsx_vftintrm_l_d,
            lsx_vfrintrne_s, lsx_vfrintrne_d, lsx_vfrintrz_s,
            lsx_vfrintrz_d, lsx_vfrintrp_s, lsx_vfrintrp_d,
            lsx_vfrintrm_s, lsx_vfrintrm_d,
            <FRINT_S:frint_pattern_s>v4sf2,
            <FRINT_D:frint_pattern_d>v2df2, round<mode>2,
            fix_trunc<mode>2): Remove.
            * config/loongarch/lasx.md: Likewise.
            * config/loongarch/simd.md: New file.
            (ILSX, ILASX, FLSX, FLASX, VIMODE): ... here.
            (IVEC, FVEC): New mode iterators.
            (VIMODE): ... here.  Extend it to work for all LSX/LASX vector
            modes.
            (x, wu, simd_isa, WVEC, vimode, simdfmt, simdifmt_for_f,
            elebits): New mode attributes.
            (UNSPEC_SIMD_FRINTRP, UNSPEC_SIMD_FRINTRZ, UNSPEC_SIMD_FRINT,
            UNSPEC_SIMD_FRINTRM, UNSPEC_SIMD_FRINTRNE): New unspecs.
            (SIMD_FRINT): New int iterator.
            (simd_frint_rounding, simd_frint_pattern): New int attributes.
            (<simd_isa>_<x>vfrint<simd_frint_rounding>_<simdfmt>): New
            define_insn template for frint instructions.
           
(<simd_isa>_<x>vftint<simd_frint_rounding>_<simdifmt_for_f>_<simdfmt>):
            Likewise, but for ftint instructions.
            (<simd_frint_pattern><mode>2): New define_expand with
            flag_fp_int_builtin_inexact checked.
            (l<simd_frint_pattern><mode><vimode>2): Likewise.
            (ftrunc<mode>2): New define_expand.  It does not require
            flag_fp_int_builtin_inexact.
            (fix_trunc<mode><vimode>2): New define_insn_and_split.  It does
            not require flag_fp_int_builtin_inexact.
            (include): Add lsx.md and lasx.md.
            * config/loongarch/loongarch.md (include): Include simd.md,
            instead of including lsx.md and lasx.md directly.
            * config/loongarch/loongarch-builtins.cc
            (CODE_FOR_lsx_vftint_w_s, CODE_FOR_lsx_vftint_l_d,
            CODE_FOR_lasx_xvftint_w_s, CODE_FOR_lasx_xvftint_l_d):
            Remove.

    gcc/testsuite/ChangeLog:

            PR target/112578
            * gcc.target/loongarch/vect-frint.c: New test.
            * gcc.target/loongarch/vect-frint-no-inexact.c: New test.
            * gcc.target/loongarch/vect-ftint.c: New test.
            * gcc.target/loongarch/vect-ftint-no-inexact.c: New test.

[Bug target/112578] LoongArch: Wrong code -with -mlsx -fno-fp-int-builtin-inexact

[xry111 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112578

Xi Ruoyao <xry111 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #6 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
Fixed for trunk.