[Bug libstdc++/96279] New: build failure: floating_from_chars.cc:310:22: error: '__builtin_isinf_sign' is not a member of 'std'

[Bug libstdc++/96279] New: build failure: floating_from_chars.cc:310:22: error: '__builtin_isinf_sign' is not a member of 'std'

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96279

            Bug ID: 96279
           Summary: build failure: floating_from_chars.cc:310:22: error:
                    '__builtin_isinf_sign' is not a member of 'std'
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: build
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: powerpc-unknown-linux-gnu

Recently the gcc build started failing; configured with:

--enable-languages=c,c++ --enable-valgrind-annotations --disable-nls
--enable-checking=yes,rtl,df,extra --with-cloog --with-ppl --with-isl
--with-sysroot=/usr/powerpc-unknown-linux-gnu --build=x86_64-pc-linux-gnu
--host=x86_64-pc-linux-gnu --target=powerpc-unknown-linux-gnu
--with-ld=/usr/bin/powerpc-unknown-linux-gnu-ld
--with-as=/usr/bin/powerpc-unknown-linux-gnu-as --disable-libstdcxx-pch

fails with:
libtool: compile:  /repo/build-gcc-trunk-powerpc/./gcc/xgcc -shared-libgcc
-B/repo/build-gcc-trunk-powerpc/./gcc -nostdinc++
-L/repo/build-gcc-trunk-powerpc/powerpc-unknown-linux-gnu/nof/libstdc++-v3/src
-L/repo/build-gcc-trunk-powerpc/powerpc-unknown-linux-gnu/nof/libstdc++-v3/src/.libs
-L/repo/build-gcc-trunk-powerpc/powerpc-unknown-linux-gnu/nof/libstdc++-v3/libsupc++/.libs
-B/repo/gcc-trunk//binary-trunk-r11-2261-20200722034646-gfb1de6a8543-checking-yes-rtl-df-extra-powerpc/powerpc-unknown-linux-gnu/bin/
-B/repo/gcc-trunk//binary-trunk-r11-2261-20200722034646-gfb1de6a8543-checking-yes-rtl-df-extra-powerpc/powerpc-unknown-linux-gnu/lib/
-isystem
/repo/gcc-trunk//binary-trunk-r11-2261-20200722034646-gfb1de6a8543-checking-yes-rtl-df-extra-powerpc/powerpc-unknown-linux-gnu/include
-isystem
/repo/gcc-trunk//binary-trunk-r11-2261-20200722034646-gfb1de6a8543-checking-yes-rtl-df-extra-powerpc/powerpc-unknown-linux-gnu/sys-include
-msoft-float -fPIC -mstrict-align -I/repo/gcc-trunk/libstdc++-v3/../libgcc
-I/repo/build-gcc-trunk-powerpc/powerpc-unknown-linux-gnu/nof/libstdc++-v3/include/powerpc-unknown-linux-gnu
-I/repo/build-gcc-trunk-powerpc/powerpc-unknown-linux-gnu/nof/libstdc++-v3/include
-I/repo/gcc-trunk/libstdc++-v3/libsupc++ -std=gnu++17 -D_GLIBCXX_SHARED
-fno-implicit-templates -Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi=2
-fdiagnostics-show-location=once -ffunction-sections -fdata-sections
-frandom-seed=floating_from_chars.lo -fimplicit-templates -g -O2 -D_GNU_SOURCE
-msoft-float -fPIC -mstrict-align -c
/repo/gcc-trunk/libstdc++-v3/src/c++17/floating_from_chars.cc  -fPIC -DPIC
-D_GLIBCXX_SHARED -o floating_from_chars.o
In file included from
/repo/build-gcc-trunk-powerpc/powerpc-unknown-linux-gnu/nof/libstdc++-v3/include/cmath:45,
                 from
/repo/gcc-trunk/libstdc++-v3/src/c++17/floating_from_chars.cc:33:
/repo/gcc-trunk/libstdc++-v3/src/c++17/floating_from_chars.cc: In function
'std::ptrdiff_t std::{anonymous}::from_chars_impl(const char*, T&,
std::errc&)':
/repo/gcc-trunk/libstdc++-v3/src/c++17/floating_from_chars.cc:310:22: error:
'__builtin_isinf_sign' is not a member of 'std'; did you mean
'__builtin_isinf_sign'?
  310 |             if (std::isinf(tmpval)) // overflow
      |                      ^~~~~
<built-in>: note: '__builtin_isinf_sign' declared here
make[9]: *** [Makefile:572: floating_from_chars.lo] Error 1

[Bug libstdc++/96279] build failure: floating_from_chars.cc:310:22: error: '__builtin_isinf_sign' is not a member of 'std'

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96279

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
looks like a bogus #define leaking in from somewhere.  Maybe you can provide
preprocessed source with -dD (that preserves #define directives in the output)

[Bug libstdc++/96279] build failure: floating_from_chars.cc:310:22: error: '__builtin_isinf_sign' is not a member of 'std'

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96279

--- Comment #2 from Zdenek Sojka <zsojka at seznam dot cz> ---
Created attachment 48914
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48914&action=edit
preprocessed source

(In reply to Richard Biener from comment #1)
> looks like a bogus #define leaking in from somewhere.  Maybe you can provide
> preprocessed source with -dD (that preserves #define directives in the
> output)

Thank you for the suggestion.

The #define comes from:
# 948 "/usr/powerpc-unknown-linux-gnu/usr/include/math.h" 3 4
#define isinf(x) __builtin_isinf_sign (x)

which belongs to package cross-powerpc-unknown-linux-gnu/glibc-2.31-r6

[Bug libstdc++/96279] build failure: floating_from_chars.cc:310:22: error: '__builtin_isinf_sign' is not a member of 'std'

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96279

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |redi at gcc dot gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2020-07-22
     Ever confirmed|0                           |1

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
<cmath> has:

#if _GLIBCXX_USE_C99_MATH
#if !_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC

// These are possible macros imported from C99-land.
#undef fpclassify
#undef isfinite
#undef isinf

So for your glibc isinf macro to be preserved we must not be using C99, which
seems lik a bug. glibc-2.31 certainly has a usable C99 implementation, so it
looks like a cross-config bug in libstdc++. It's probably been there for years
and we never noticed until now.

[Bug libstdc++/96279] build failure: floating_from_chars.cc:310:22: error: '__builtin_isinf_sign' is not a member of 'std'

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96279

--- Comment #4 from Zdenek Sojka <zsojka at seznam dot cz> ---
I can no longer reproduce this: r11-2420 (BAD), r11-2449 (OK)

[Bug libstdc++/96279] build failure: floating_from_chars.cc:310:22: error: '__builtin_isinf_sign' is not a member of 'std'

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96279

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed by r11-2439 but I want to keep this open because the cross-config is
still wrong.

[Bug libstdc++/96279] build failure: floating_from_chars.cc:310:22: error: '__builtin_isinf_sign' is not a member of 'std'

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96279

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |NEW
           Assignee|redi at gcc dot gnu.org            |unassigned at gcc dot gnu.org