[PATCH] math: Fix x86_64 build for -Os (BZ 33367)

Mon Sep 8 15:08:12 GMT 2025

On 08/09/25 11:26, H.J. Lu wrote:
> On Sat, Sep 6, 2025 at 3:22 PM Adhemerval Zanella
> <adhemerval.zanella@linaro.org> wrote:
>>
>> The compiler might not inline the trunc function call for
>> USE_TRUNC_BUILTIN, which requires adding the required objects.
>>
>> Route trunc calls for the optimized modf variants to thei
>> ABI-compatible version. This avoids invoking the ifunc variant
>> for x86_64-v1 and requires fewer objects to be added.
>>
>> Checked on x86_64, x86_64-v2, x86_64-v3, and x86_64-v4. Used -O2 and
>> -Os options. Performed a full make check on x86_64 with both
>>  optimizations.
>> ---
>>  sysdeps/x86_64/fpu/multiarch/Makefile         | 19 ++++++++++++-------
>>  sysdeps/x86_64/fpu/multiarch/s_modf-avx.c     |  5 +++++
>>  sysdeps/x86_64/fpu/multiarch/s_modf-sse4_1.c  |  5 +++++
>>  sysdeps/x86_64/fpu/multiarch/s_modf.c         |  1 -
>>  sysdeps/x86_64/fpu/multiarch/s_modff-avx.c    |  5 +++++
>>  sysdeps/x86_64/fpu/multiarch/s_modff-sse4_1.c |  5 +++++
>>  sysdeps/x86_64/fpu/multiarch/s_modff.c        |  1 -
>>  7 files changed, 32 insertions(+), 9 deletions(-)
>>
>> diff --git a/sysdeps/x86_64/fpu/multiarch/Makefile b/sysdeps/x86_64/fpu/multiarch/Makefile
>> index 708b14297f..baefe8dd07 100644
>> --- a/sysdeps/x86_64/fpu/multiarch/Makefile
>> +++ b/sysdeps/x86_64/fpu/multiarch/Makefile
>> @@ -26,6 +26,11 @@ CFLAGS-s_sinf-fma.c = -mfma -mavx2
>>  CFLAGS-s_cosf-fma.c = -mfma -mavx2
>>  CFLAGS-s_sincosf-fma.c = -mfma -mavx2
>>
>> +sysdep_calls += \
>> +  s_trunc-sse4_1 \
>> +  s_truncf-sse4_1 \
>> +# sysdep_calls
>> +
>>  # Check if ISA level is 2 or above.
>>  ifeq (,$(filter $(have-x86-isa-level),$(x86-isa-level-2-or-above)))
>>  sysdep_calls += \
>> @@ -36,6 +41,10 @@ endif
>>
>>  # Check if ISA level is 3 or above.
>>  ifneq (,$(filter $(have-x86-isa-level),$(x86-isa-level-3-or-above)))
>> +sysdep_calls += \
>> +  s_trunc-avx \
>> +  s_truncf-avx \
>> +# sysdep_calls
>>  libm-sysdep_routines += \
>>    s_ceil-avx \
>>    s_ceilf-avx \
>> @@ -47,8 +56,6 @@ libm-sysdep_routines += \
>>    s_rintf-avx \
>>    s_roundeven-avx \
>>    s_roundevenf-avx \
>> -  s_trunc-avx \
>> -  s_truncf-avx \
>>  # libm-sysdep_routines
>>  else
>>  sysdep_calls += \
>> @@ -114,8 +121,6 @@ libm-sysdep_routines += \
>>    s_tan-avx \
>>    s_tan-fma \
>>    s_tanh-fma \
>> -  s_trunc-sse4_1 \
>> -  s_truncf-sse4_1 \
>>  # libm-sysdep_routines
>>  ifeq ($(have-x86-isa-level),baseline)
>>  libm-sysdep_routines += \
>> @@ -132,13 +137,13 @@ libm-sysdep_routines += \
>>    s_trunc-c \
>>    s_truncf-c \
>>  # libm-sysdep_routines
>> -endif
>> +endif # ($(have-x86-isa-level),baseline)
>> +endif # (,$(filter $(have-x86-isa-level),$(x86-isa-level-3-or-above)))
>>
>>  # $(sysdep_calls) functions are built both for libc and libm.  While the
>>  # libc objects have the prefix s_, the libm ones are prefixed with m_.
>> -sysdep_routines += $(sysdep_calls)
>> +sysdep_routines +=  $(sysdep_calls)
>>  libm-sysdep_routines += $(sysdep_calls:s_%=m_%)
>> -endif
>>
>>  CFLAGS-e_asin-fma4.c = -mfma4
>>  CFLAGS-e_atan2-fma4.c = -mfma4
>> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modf-avx.c b/sysdeps/x86_64/fpu/multiarch/s_modf-avx.c
>> index ab4f03db0e..25617c4fdc 100644
>> --- a/sysdeps/x86_64/fpu/multiarch/s_modf-avx.c
>> +++ b/sysdeps/x86_64/fpu/multiarch/s_modf-avx.c
>> @@ -1,3 +1,8 @@
>> +#include <sysdeps/x86/isa-level.h>
>> +#if MINIMUM_X86_ISA_LEVEL < SSE4_1_X86_ISA_LEVEL
>> +asm ("__trunc = __trunc_sse41");
> 
> It looks odd for __modf_avx to call __trunc_sse41.   But this is a
> separate issue.
> We do have s_truncf-avx.S, but it isn't used by default.  I think we should
> make it available for s_modf.c and s_modf-avx.c first.

This will add an extra patch to backport, can we make it after this
fix?

> 
>> +#endif
>> +
>>  #define __modf __modf_avx
>>
>>  #include <sysdeps/ieee754/dbl-64/s_modf.c>
>> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modf-sse4_1.c b/sysdeps/x86_64/fpu/multiarch/s_modf-sse4_1.c
>> index 00aa8cd736..086499282e 100644
>> --- a/sysdeps/x86_64/fpu/multiarch/s_modf-sse4_1.c
>> +++ b/sysdeps/x86_64/fpu/multiarch/s_modf-sse4_1.c
>> @@ -1,3 +1,8 @@
>> +#include <sysdeps/x86/isa-level.h>
>> +#if MINIMUM_X86_ISA_LEVEL < SSE4_1_X86_ISA_LEVEL
>> +asm ("__trunc = __trunc_sse41");
>> +#endif
>> +
>>  #define __modf __modf_sse41
>>
>>  #include <sysdeps/ieee754/dbl-64/s_modf.c>
>> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modf.c b/sysdeps/x86_64/fpu/multiarch/s_modf.c
>> index e365bfcef7..dc5d7931c8 100644
>> --- a/sysdeps/x86_64/fpu/multiarch/s_modf.c
>> +++ b/sysdeps/x86_64/fpu/multiarch/s_modf.c
>> @@ -18,7 +18,6 @@
>>
>>  #include <sysdeps/x86/isa-level.h>
>>  #if MINIMUM_X86_ISA_LEVEL < AVX_X86_ISA_LEVEL
>> -# define NO_MATH_REDIRECT
>>  # include <libm-alias-double.h>
>>
>>  # define modf __redirect_modf
>> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modff-avx.c b/sysdeps/x86_64/fpu/multiarch/s_modff-avx.c
>> index 07cb9c1036..dd5e37b569 100644
>> --- a/sysdeps/x86_64/fpu/multiarch/s_modff-avx.c
>> +++ b/sysdeps/x86_64/fpu/multiarch/s_modff-avx.c
>> @@ -1,3 +1,8 @@
>> +#include <sysdeps/x86/isa-level.h>
>> +#if MINIMUM_X86_ISA_LEVEL < SSE4_1_X86_ISA_LEVEL
>> +asm ("__truncf = __truncf_sse41");
>> +#endif
>> +
>>  #define __modff __modff_avx
>>
>>  #include <sysdeps/ieee754/flt-32/s_modff.c>
>> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modff-sse4_1.c b/sysdeps/x86_64/fpu/multiarch/s_modff-sse4_1.c
>> index 060c5e3979..bf73ba3517 100644
>> --- a/sysdeps/x86_64/fpu/multiarch/s_modff-sse4_1.c
>> +++ b/sysdeps/x86_64/fpu/multiarch/s_modff-sse4_1.c
>> @@ -1,3 +1,8 @@
>> +#include <sysdeps/x86/isa-level.h>
>> +#if MINIMUM_X86_ISA_LEVEL < SSE4_1_X86_ISA_LEVEL
>> +asm ("__truncf = __truncf_sse41");
>> +#endif
>> +
>>  #define __modff __modff_sse41
>>
>>  #include <sysdeps/ieee754/flt-32/s_modff.c>
>> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modff.c b/sysdeps/x86_64/fpu/multiarch/s_modff.c
>> index a4b5429037..f7351677a1 100644
>> --- a/sysdeps/x86_64/fpu/multiarch/s_modff.c
>> +++ b/sysdeps/x86_64/fpu/multiarch/s_modff.c
>> @@ -18,7 +18,6 @@
>>
>>  #include <sysdeps/x86/isa-level.h>
>>  #if MINIMUM_X86_ISA_LEVEL < AVX_X86_ISA_LEVEL
>> -# define NO_MATH_REDIRECT
>>  # include <libm-alias-float.h>
>>
>>  # define modff __redirect_modff
>> --
>> 2.43.0
>>
> 
> 