From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org
Subject: [PATCH 00/12] Improve rounding to interger function for C23
Date: Thu, 28 Dec 2023 14:20:14 -0300 [thread overview]
Message-ID: <20231228172026.2013007-1-adhemerval.zanella@linaro.org> (raw)
As indicated by GCC documentation [1], ISO C23 does not allow that C
bindings ceil, floor, round, and trunc (in all floating point formats)
to raise
inexact exceptions (different than ISO C99/C11 where this is allowed).
A recent MIPS patch to used some arch-specific instructions raised this
issue [1] and it was not caught because there was no proper testing. By
adding the missing tests, some implementations do indeed raise inexact
exceptions.
The generic implementation all uses integer operation, so they are not
subject to this issue. The powerpc (for power4 and lower) and the riscv
avoid the inexact exception by disabling/enabling exceptions. The x86
uses some arch-specific implementation for long double and on i386 (due
to the use of x87 instruction).
Instead of adding newer symbols depending on the required standard
version, the patchset adapts the faulty ones to avoid raising the
inexact exception. The x86 version already saves/restore the floating
point status, so I think it is unlikely the patch would yield much
performance difference (I did not do any performance analysis on whether
a generic implementation would yield better performance).
I checked on powerpc, powerpc64, aarch64, armhf, x86, and did some
regression checks on riscv.
[1] https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fno-fp-int-builtin-inexact
[2] https://sourceware.org/pipermail/libc-alpha/2023-December/153528.html
Adhemerval Zanella (12):
math: Reformat Makefile.
powerpc: Add missing arch flags on rounding ifunc variants
math: Add test to check if ceil raise inexact floating-point exception
math: Add test to check if floor raise inexact floating-point
exception
math: Add test to check if trunc raise inexact floating-point
exception
math: Add test to check if round raise inexact floating-point
exception
x86: Do not raise inexact exception on ceill
x86: Do not raise inexact exception on floorl
x86: Do not raise inexact exception on truncl
x86: Do not raise inexact exception on floor/floorf
i386: Do not raise inexact exception on ceil/ceilf
i386: Do not raise inexact exception on trunc/truncf
math/Makefile | 861 ++++++++++++++----
math/test-ceil-except-2.c | 67 ++
math/test-ceil-except.c | 85 ++
math/test-floor-except-2.c | 67 ++
math/test-floor-except.c | 85 ++
math/test-round-except-2.c | 67 ++
math/test-round-except.c | 85 ++
math/test-trunc-except-2.c | 67 ++
math/test-trunc-except.c | 85 ++
sysdeps/i386/fpu/s_ceil.S | 34 -
sysdeps/i386/fpu/s_ceil.c | 38 +
sysdeps/i386/fpu/s_ceilf.S | 34 -
sysdeps/i386/fpu/s_ceilf.c | 38 +
sysdeps/i386/fpu/s_ceill.S | 39 -
sysdeps/i386/fpu/s_floor.S | 34 -
sysdeps/i386/fpu/s_floor.c | 38 +
sysdeps/i386/fpu/s_floorf.S | 34 -
sysdeps/i386/fpu/s_floorf.c | 38 +
sysdeps/i386/fpu/s_floorl.S | 39 -
sysdeps/i386/fpu/{s_trunc.S => s_trunc.c} | 37 +-
sysdeps/i386/fpu/{s_truncf.S => s_truncf.c} | 37 +-
.../powerpc32/power4/fpu/multiarch/Makefile | 6 +
.../fpu/s_truncl.S => x86/fpu/s_ceill.c} | 38 +-
sysdeps/x86/fpu/s_floorl.c | 38 +
.../fpu/s_truncl.S => x86/fpu/s_truncl.c} | 40 +-
sysdeps/x86_64/fpu/s_ceill.S | 34 -
sysdeps/x86_64/fpu/s_floorl.S | 33 -
27 files changed, 1583 insertions(+), 515 deletions(-)
create mode 100644 math/test-ceil-except-2.c
create mode 100644 math/test-ceil-except.c
create mode 100644 math/test-floor-except-2.c
create mode 100644 math/test-floor-except.c
create mode 100644 math/test-round-except-2.c
create mode 100644 math/test-round-except.c
create mode 100644 math/test-trunc-except-2.c
create mode 100644 math/test-trunc-except.c
delete mode 100644 sysdeps/i386/fpu/s_ceil.S
create mode 100644 sysdeps/i386/fpu/s_ceil.c
delete mode 100644 sysdeps/i386/fpu/s_ceilf.S
create mode 100644 sysdeps/i386/fpu/s_ceilf.c
delete mode 100644 sysdeps/i386/fpu/s_ceill.S
delete mode 100644 sysdeps/i386/fpu/s_floor.S
create mode 100644 sysdeps/i386/fpu/s_floor.c
delete mode 100644 sysdeps/i386/fpu/s_floorf.S
create mode 100644 sysdeps/i386/fpu/s_floorf.c
delete mode 100644 sysdeps/i386/fpu/s_floorl.S
rename sysdeps/i386/fpu/{s_trunc.S => s_trunc.c} (61%)
rename sysdeps/i386/fpu/{s_truncf.S => s_truncf.c} (61%)
rename sysdeps/{x86_64/fpu/s_truncl.S => x86/fpu/s_ceill.c} (57%)
create mode 100644 sysdeps/x86/fpu/s_floorl.c
rename sysdeps/{i386/fpu/s_truncl.S => x86/fpu/s_truncl.c} (61%)
delete mode 100644 sysdeps/x86_64/fpu/s_ceill.S
delete mode 100644 sysdeps/x86_64/fpu/s_floorl.S
--
2.34.1
next reply other threads:[~2023-12-28 17:21 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-28 17:20 Adhemerval Zanella [this message]
2023-12-28 17:20 ` [PATCH 01/12] math: Reformat Makefile Adhemerval Zanella
2024-04-01 13:57 ` H.J. Lu
2023-12-28 17:20 ` [PATCH 02/12] powerpc: Add missing arch flags on rounding ifunc variants Adhemerval Zanella
2024-04-01 13:59 ` H.J. Lu
2024-04-01 16:50 ` Peter Bergner
2023-12-28 17:20 ` [PATCH 03/12] math: Add test to check if ceil raise inexact floating-point exception Adhemerval Zanella
2024-04-01 14:01 ` H.J. Lu
2023-12-28 17:20 ` [PATCH 04/12] math: Add test to check if floor " Adhemerval Zanella
2024-04-01 14:02 ` H.J. Lu
2023-12-28 17:20 ` [PATCH 05/12] math: Add test to check if trunc " Adhemerval Zanella
2024-04-01 14:03 ` H.J. Lu
2023-12-28 17:20 ` [PATCH 06/12] math: Add test to check if round " Adhemerval Zanella
2024-04-01 14:02 ` H.J. Lu
2023-12-28 17:20 ` [PATCH 07/12] x86: Do not raise inexact exception on ceill Adhemerval Zanella
2024-04-01 14:12 ` H.J. Lu
2023-12-28 17:20 ` [PATCH 08/12] x86: Do not raise inexact exception on floorl Adhemerval Zanella
2024-04-01 14:13 ` H.J. Lu
2023-12-28 17:20 ` [PATCH 09/12] x86: Do not raise inexact exception on truncl Adhemerval Zanella
2024-04-01 14:14 ` H.J. Lu
2023-12-28 17:20 ` [PATCH 10/12] x86: Do not raise inexact exception on floor/floorf Adhemerval Zanella
2024-04-01 14:15 ` H.J. Lu
2023-12-28 17:20 ` [PATCH 11/12] i386: Do not raise inexact exception on ceil/ceilf Adhemerval Zanella
2024-04-01 14:16 ` H.J. Lu
2023-12-28 17:20 ` [PATCH 12/12] i386: Do not raise inexact exception on trunc/truncf Adhemerval Zanella
2024-04-01 14:17 ` H.J. Lu
2024-02-16 17:47 ` [PATCH 00/12] Improve rounding to interger function for C23 Adhemerval Zanella Netto
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