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

[Sam James]

Sam James <sam@gentoo.org> writes:

> "H.J. Lu" <hjl.tools@gmail.com> writes:
>
>> On Mon, Sep 8, 2025 at 2:05 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>>>
>>> On Mon, Sep 8, 2025 at 2:01 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>>> >
>>
>>> >
>>>
>>> My GCC patch:
>>>
>>> https://patchwork.sourceware.org/project/gcc/list/?series=51782
>>>
>>> I am testing this:
>>>
>>> diff --git a/sysdeps/x86_64/fpu/multiarch/Makefile
>>> b/sysdeps/x86_64/fpu/multiarch/Makefile
>>> index 708b14297f..0b2caac7a0 100644
>>> --- a/sysdeps/x86_64/fpu/multiarch/Makefile
>>> +++ b/sysdeps/x86_64/fpu/multiarch/Makefile
>>> @@ -158,11 +158,14 @@ CFLAGS-s_sin-avx.c = -msse2avx -DSSE2AVX
>>>  CFLAGS-s_tan-avx.c = -msse2avx -DSSE2AVX
>>>  CFLAGS-s_sincos-avx.c = -msse2avx -DSSE2AVX
>>>
>>> -CFLAGS-s_modf-sse4_1.c = -msse4.1 -fno-builtin-modff32x -fno-builtin-modff64
>>> -CFLAGS-s_modff-sse4_1.c = -msse4.1 -fno-builtin-modff32
>>> +CFLAGS-s_modf-sse4_1.c = -msse4.1 -fno-builtin-modff32x \
>>> + -fno-builtin-modff64 -fno-trapping-math
>>> +CFLAGS-s_modff-sse4_1.c = -msse4.1 -fno-builtin-modff32 \
>>> + -fno-trapping-math
>>>
>>> -CFLAGS-s_modf-avx.c = -mavx -fno-builtin-modff32x -fno-builtin-modff64
>>> -CFLAGS-s_modff-avx.c = -mavx -fno-builtin-modff32
>>> +CFLAGS-s_modf-avx.c = -mavx -fno-builtin-modff32x -fno-builtin-modff64 \
>>> +       -fno-trapping-math
>>> +CFLAGS-s_modff-avx.c = -mavx -fno-builtin-modff32 -fno-trapping-math
>>>  endif
>>>
>>>  ifeq ($(subdir),mathvec)
>>>
>>
>> I got many failures:
>>
>> FAIL: ctype/tst-ctype-tls-dlopen-static
>> FAIL: debug/tst-sprintf-fortify-rdonly-static
>> FAIL: dlfcn/tststatic
>> FAIL: dlfcn/tststatic2
>> FAIL: dlfcn/tststatic3
>> FAIL: dlfcn/tststatic4
>> FAIL: dlfcn/tststatic5
>> FAIL: elf/ifuncmain1picstatic
>> FAIL: elf/ifuncmain1static
>> FAIL: elf/ifuncmain2picstatic
>> FAIL: elf/ifuncmain2static
>> FAIL: elf/ifuncmain4picstatic
>> FAIL: elf/ifuncmain4static
>> FAIL: elf/ifuncmain5picstatic
>> FAIL: elf/ifuncmain5static
>> FAIL: elf/ifuncmain7picstatic
>> FAIL: elf/ifuncmain7static
>> FAIL: elf/ifuncmain9picstatic
>> FAIL: elf/ifuncmain9static
>> FAIL: elf/tst-array1-static
>> FAIL: elf/tst-array1-static-cmp
>> FAIL: elf/tst-array5-static
>> FAIL: elf/tst-array5-static-cmp
>> FAIL: elf/tst-bz15311
>> FAIL: elf/tst-bz28937
>> FAIL: elf/tst-cpu-features-cpuinfo-static
>> FAIL: elf/tst-cpu-features-supports-static
>> FAIL: elf/tst-dl-iter-static
>> FAIL: elf/tst-dl-printf-static
>> FAIL: elf/tst-dl_find_object-static
>> FAIL: elf/tst-dlopen-sgid
>> FAIL: elf/tst-dso-ordering-all2-0
>> FAIL: elf/tst-dso-ordering-all3-0
>> FAIL: elf/tst-dso-ordering-all3-1
>> FAIL: elf/tst-dso-ordering-all3-2
>> FAIL: elf/tst-dso-ordering-all3-3
>> FAIL: elf/tst-dso-ordering-all4-0
>> FAIL: elf/tst-dso-ordering-all4-1
>> FAIL: elf/tst-dso-ordering-all4-10
>> FAIL: elf/tst-dso-ordering-all4-11
>> FAIL: elf/tst-dso-ordering-all4-12
>> FAIL: elf/tst-dso-ordering-all4-13
>> FAIL: elf/tst-dso-ordering-all4-14
>> FAIL: elf/tst-dso-ordering-all4-15
>> FAIL: elf/tst-dso-ordering-all4-16
>> FAIL: elf/tst-dso-ordering-all4-17
>> FAIL: elf/tst-dso-ordering-all4-18
>> FAIL: elf/tst-dso-ordering-all4-19
>> FAIL: elf/tst-dso-ordering-all4-2
>> FAIL: elf/tst-dso-ordering-all4-20
>> FAIL: elf/tst-dso-ordering-all4-21
>> FAIL: elf/tst-dso-ordering-all4-22
>> FAIL: elf/tst-dso-ordering-all4-23
>> FAIL: elf/tst-dso-ordering-all4-24
>> FAIL: elf/tst-dso-ordering-all4-25
>> FAIL: elf/tst-dso-ordering-all4-26
>> FAIL: elf/tst-dso-ordering-all4-27
>> FAIL: elf/tst-dso-ordering-all4-28
>> FAIL: elf/tst-dso-ordering-all4-29
>> FAIL: elf/tst-dso-ordering-all4-3
>> FAIL: elf/tst-dso-ordering-all4-30
>> FAIL: elf/tst-dso-ordering-all4-31
>> FAIL: elf/tst-dso-ordering-all4-32
>> FAIL: elf/tst-dso-ordering-all4-33
>> FAIL: elf/tst-dso-ordering-all4-34
>> FAIL: elf/tst-dso-ordering-all4-35
>> FAIL: elf/tst-dso-ordering-all4-36
>> FAIL: elf/tst-dso-ordering-all4-37
>> FAIL: elf/tst-dso-ordering-all4-38
>> FAIL: elf/tst-dso-ordering-all4-39
>> FAIL: elf/tst-dso-ordering-all4-4
>> FAIL: elf/tst-dso-ordering-all4-40
>> FAIL: elf/tst-dso-ordering-all4-41
>> FAIL: elf/tst-dso-ordering-all4-42
>> FAIL: elf/tst-dso-ordering-all4-43
>> FAIL: elf/tst-dso-ordering-all4-44
>> FAIL: elf/tst-dso-ordering-all4-45
>> FAIL: elf/tst-dso-ordering-all4-46
>> FAIL: elf/tst-dso-ordering-all4-47
>> FAIL: elf/tst-dso-ordering-all4-48
>> FAIL: elf/tst-dso-ordering-all4-49
>> FAIL: elf/tst-dso-ordering-all4-5
>> FAIL: elf/tst-dso-ordering-all4-50
>> FAIL: elf/tst-dso-ordering-all4-51
>> FAIL: elf/tst-dso-ordering-all4-52
>> FAIL: elf/tst-dso-ordering-all4-53
>> FAIL: elf/tst-dso-ordering-all4-54
>> FAIL: elf/tst-dso-ordering-all4-55
>> FAIL: elf/tst-dso-ordering-all4-56
>> FAIL: elf/tst-dso-ordering-all4-6
>> FAIL: elf/tst-dso-ordering-all4-7
>> FAIL: elf/tst-dso-ordering-all4-8
>> FAIL: elf/tst-dso-ordering-all4-9
>> FAIL: elf/tst-dso-ordering1
>> FAIL: elf/tst-dso-ordering10
>> FAIL: elf/tst-dso-ordering2
>> FAIL: elf/tst-dso-ordering3
>> FAIL: elf/tst-dso-ordering4
>> FAIL: elf/tst-dso-ordering5
>> FAIL: elf/tst-dso-ordering6
>> FAIL: elf/tst-dso-ordering7
>> FAIL: elf/tst-dso-ordering8
>> FAIL: elf/tst-dso-ordering9
>> FAIL: elf/tst-dst-static
>> FAIL: elf/tst-env-setuid-static
>> FAIL: elf/tst-env-setuid-tunables
>> FAIL: elf/tst-execstack-prog-static
>> FAIL: elf/tst-execstack-prog-static-noexecstack
>> FAIL: elf/tst-execstack-prog-static-tunable
>> FAIL: elf/tst-get-cpu-features-static
>> FAIL: elf/tst-getauxval-static
>> FAIL: elf/tst-ldconfig-X
>> FAIL: elf/tst-ldconfig-bad-aux-cache
>> FAIL: elf/tst-ldconfig-ld_so_conf-update
>> FAIL: elf/tst-ldconfig-p
>> FAIL: elf/tst-ldconfig-soname
>> FAIL: elf/tst-linkall-static
>> FAIL: elf/tst-pie-address-static
>> FAIL: elf/tst-pie-bss-static
>> FAIL: elf/tst-ptrguard1-static
>> FAIL: elf/tst-rtld-run-static
>> FAIL: elf/tst-single_threaded-pthread-static
>> FAIL: elf/tst-single_threaded-static
>> FAIL: elf/tst-single_threaded-static-dlopen
>> FAIL: elf/tst-stackguard1-static
>> FAIL: elf/tst-tls-allocation-failure-static
>> FAIL: elf/tst-tls-allocation-failure-static-patched
>> FAIL: elf/tst-tls1-static
>> FAIL: elf/tst-tls1-static-non-pie
>> FAIL: elf/tst-tls9-static
>> FAIL: elf/tst-tlsalign-extern-static
>> FAIL: elf/tst-tlsalign-static
>> FAIL: elf/tst-tunables
>> FAIL: elf/tst-tunables-enable_secure
>> FAIL: gmon/tst-gmon-static
>> FAIL: gmon/tst-gmon-static-gprof
>> FAIL: gmon/tst-gmon-static-pie
>> FAIL: gmon/tst-gmon-static-pie-gprof
>> FAIL: inet/tst-deadline
>> FAIL: inet/tst-idna_name_classify
>> FAIL: io/tst-statx
>> FAIL: libio/tst-cleanup-default-static
>> FAIL: libio/tst-cleanup-default-static-cmp
>> FAIL: libio/tst-cleanup-nostart-stop-gc-static
>> FAIL: libio/tst-cleanup-nostart-stop-gc-static-cmp
>> FAIL: libio/tst-cleanup-start-stop-gc-static
>> FAIL: libio/tst-cleanup-start-stop-gc-static-cmp
>> FAIL: libio/tst-stdio-static
>> FAIL: localedata/bug-setlocale1-static
>> FAIL: localedata/tst-langinfo-setlocale-static
>> FAIL: malloc/tst-aligned-alloc-static
>> FAIL: malloc/tst-interpose-static-nothread
>> FAIL: malloc/tst-interpose-static-thread
>> FAIL: math/atest-exp
>> FAIL: math/atest-exp2
>> FAIL: math/atest-sincos
>> FAIL: math/test-fpucw-ieee-static
>> FAIL: math/test-fpucw-static
>> FAIL: math/test-signgam-uchar-init-static
>> FAIL: math/test-signgam-uchar-static
>> FAIL: math/test-signgam-uint-init-static
>> FAIL: math/test-signgam-uint-static
>> FAIL: math/test-signgam-ullong-init-static
>> FAIL: math/test-signgam-ullong-static
>> FAIL: misc/tst-align-clone-internal
>> FAIL: misc/tst-clone2-internal
>> FAIL: misc/tst-clone3-internal
>> FAIL: misc/tst-empty
>> FAIL: misc/tst-fd_to_filename
>> FAIL: misc/tst-getpid1-internal
>> FAIL: nptl/tst-cancel21-static
>> FAIL: nptl/tst-cancel24-static
>> FAIL: nptl/tst-cond11-static
>> FAIL: nptl/tst-cond8-static
>> FAIL: nptl/tst-locale1
>> FAIL: nptl/tst-locale2
>> FAIL: nptl/tst-mutex8-static
>> FAIL: nptl/tst-mutexpi8-static
>> FAIL: nptl/tst-pthread-gdb-attach-static
>> FAIL: nptl/tst-pthread-key1-static
>> FAIL: nptl/tst-pthread_exit-nothreads-static
>> FAIL: nptl/tst-sem11-static
>> FAIL: nptl/tst-sem12-static
>> FAIL: nptl/tst-stackguard1-static
>> FAIL: nss/tst-field
>> FAIL: posix/tst-affinity-static
>> FAIL: posix/tst-exec-static
>> FAIL: posix/tst-libc-message
>> FAIL: posix/tst-spawn-static
>> FAIL: posix/tst-sysconf-cache-linesize-static
>> FAIL: resolv/tst-ns_name_length_uncompressed
>> FAIL: resolv/tst-ns_rr_cursor
>> FAIL: resolv/tst-ns_samebinaryname
>> FAIL: resolv/tst-resolv-txnid-collision
>> FAIL: setjmp/tst-setjmp-static
>> FAIL: stdlib/tst-getenv-static
>> FAIL: stdlib/tst-secure-getenv
>> FAIL: string/test-memswap
>
> It's not obvious to me how modf{,f} is used at all for any of that. I
> also thought from the thread that the codegen would be basically the
> same as it is with -O2 now. What's going on?

Nevermind, I see other changes. But still, I don't see how it can lead
to such breakage. Does the same happen with azanela's inline asm patch?
Is glibc miscompiled at -Os and nobody noticed (independent of modf*)?

>
>>
>> -O2 works.