[libc-commits] [libc] [libc][math][c++23] Add bfloat16 support in LLVM libc (PR #144463)

[LLVM Continuous Integration via libc-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `libc-riscv64-debian-fullbuild-dbg` running on `libc-riscv64-debian` while building `libc` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/183/builds/15780

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 4 (annotate) failure: 'python ../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py ...' (failure)
...
[89/454] Building CXX object libc/src/stdbit/CMakeFiles/libc.src.stdbit.stdc_count_zeros_us.dir/stdc_count_zeros_us.cpp.o
[90/454] Building CXX object libc/src/stdbit/CMakeFiles/libc.src.stdbit.stdc_count_zeros_ui.dir/stdc_count_zeros_ui.cpp.o
[91/454] Building CXX object libc/src/stdbit/CMakeFiles/libc.src.stdbit.stdc_count_zeros_ull.dir/stdc_count_zeros_ull.cpp.o
[92/454] Building CXX object libc/src/stdbit/CMakeFiles/libc.src.stdbit.stdc_count_zeros_ul.dir/stdc_count_zeros_ul.cpp.o
[93/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.fopencookie.dir/fopencookie.cpp.o
[94/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.flockfile.dir/flockfile.cpp.o
[95/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.funlockfile.dir/funlockfile.cpp.o
[96/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.setbuf.dir/setbuf.cpp.o
[97/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.setvbuf.dir/setvbuf.cpp.o
[98/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.sprintf.dir/sprintf.cpp.o
FAILED: libc/src/stdio/CMakeFiles/libc.src.stdio.sprintf.dir/sprintf.cpp.o 
/usr/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc -isystem /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/build/libc/include -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -fdiagnostics-color -g -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -DLIBC_ERRNO_MODE=LIBC_ERRNO_MODE_DEFAULT -fpie -ffreestanding -DLIBC_FULL_BUILD -nostdlibinc -idirafter/usr/include -fno-builtin -fno-exceptions -fno-lax-vector-conversions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-rtti -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wstrict-prototypes -Wthread-safety -Wglobal-constructors -DLIBC_COPT_PUBLIC_PACKAGING -DLIBC_COPT_PRINTF_RUNTIME_DISPATCH -std=gnu++17 -MD -MT libc/src/stdio/CMakeFiles/libc.src.stdio.sprintf.dir/sprintf.cpp.o -MF libc/src/stdio/CMakeFiles/libc.src.stdio.sprintf.dir/sprintf.cpp.o.d -o libc/src/stdio/CMakeFiles/libc.src.stdio.sprintf.dir/sprintf.cpp.o -c /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/sprintf.cpp
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/sprintf.cpp:14:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/printf_main.h:14:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter.h:21:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter_atlas.h:32:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/float_dec_converter.h:17:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/float_to_string.h:17:
/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/FPUtil/dyadic_float.h:419:14: error: use of function template name with no prior declaration in function call with explicit template arguments is a C++20 extension [-Werror,-Wc++20-extensions]
      return generic_as<T, ShouldSignalExceptions>();
             ^
1 error generated.
[99/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.snprintf.dir/snprintf.cpp.o
FAILED: libc/src/stdio/CMakeFiles/libc.src.stdio.snprintf.dir/snprintf.cpp.o 
/usr/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc -isystem /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/build/libc/include -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -fdiagnostics-color -g -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -DLIBC_ERRNO_MODE=LIBC_ERRNO_MODE_DEFAULT -fpie -ffreestanding -DLIBC_FULL_BUILD -nostdlibinc -idirafter/usr/include -fno-builtin -fno-exceptions -fno-lax-vector-conversions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-rtti -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wstrict-prototypes -Wthread-safety -Wglobal-constructors -DLIBC_COPT_PUBLIC_PACKAGING -DLIBC_COPT_PRINTF_RUNTIME_DISPATCH -std=gnu++17 -MD -MT libc/src/stdio/CMakeFiles/libc.src.stdio.snprintf.dir/snprintf.cpp.o -MF libc/src/stdio/CMakeFiles/libc.src.stdio.snprintf.dir/snprintf.cpp.o.d -o libc/src/stdio/CMakeFiles/libc.src.stdio.snprintf.dir/snprintf.cpp.o -c /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/snprintf.cpp
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/snprintf.cpp:13:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/printf_main.h:14:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter.h:21:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter_atlas.h:32:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/float_dec_converter.h:17:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/float_to_string.h:17:
/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/FPUtil/dyadic_float.h:419:14: error: use of function template name with no prior declaration in function call with explicit template arguments is a C++20 extension [-Werror,-Wc++20-extensions]
      return generic_as<T, ShouldSignalExceptions>();
             ^
1 error generated.
[100/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.asprintf.dir/asprintf.cpp.o
FAILED: libc/src/stdio/CMakeFiles/libc.src.stdio.asprintf.dir/asprintf.cpp.o 
/usr/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc -isystem /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/build/libc/include -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -fdiagnostics-color -g -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -DLIBC_ERRNO_MODE=LIBC_ERRNO_MODE_DEFAULT -fpie -ffreestanding -DLIBC_FULL_BUILD -nostdlibinc -idirafter/usr/include -fno-builtin -fno-exceptions -fno-lax-vector-conversions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-rtti -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wstrict-prototypes -Wthread-safety -Wglobal-constructors -DLIBC_COPT_PUBLIC_PACKAGING -DLIBC_COPT_PRINTF_RUNTIME_DISPATCH -std=gnu++17 -MD -MT libc/src/stdio/CMakeFiles/libc.src.stdio.asprintf.dir/asprintf.cpp.o -MF libc/src/stdio/CMakeFiles/libc.src.stdio.asprintf.dir/asprintf.cpp.o.d -o libc/src/stdio/CMakeFiles/libc.src.stdio.asprintf.dir/asprintf.cpp.o -c /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/asprintf.cpp
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/asprintf.cpp:12:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/vasprintf_internal.h:15:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/printf_main.h:14:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter.h:21:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter_atlas.h:32:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/float_dec_converter.h:17:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/float_to_string.h:17:
/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/FPUtil/dyadic_float.h:419:14: error: use of function template name with no prior declaration in function call with explicit template arguments is a C++20 extension [-Werror,-Wc++20-extensions]
      return generic_as<T, ShouldSignalExceptions>();
             ^
1 error generated.
Step 6 (build libc) failure: build libc (failure)
...
[89/454] Building CXX object libc/src/stdbit/CMakeFiles/libc.src.stdbit.stdc_count_zeros_us.dir/stdc_count_zeros_us.cpp.o
[90/454] Building CXX object libc/src/stdbit/CMakeFiles/libc.src.stdbit.stdc_count_zeros_ui.dir/stdc_count_zeros_ui.cpp.o
[91/454] Building CXX object libc/src/stdbit/CMakeFiles/libc.src.stdbit.stdc_count_zeros_ull.dir/stdc_count_zeros_ull.cpp.o
[92/454] Building CXX object libc/src/stdbit/CMakeFiles/libc.src.stdbit.stdc_count_zeros_ul.dir/stdc_count_zeros_ul.cpp.o
[93/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.fopencookie.dir/fopencookie.cpp.o
[94/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.flockfile.dir/flockfile.cpp.o
[95/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.funlockfile.dir/funlockfile.cpp.o
[96/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.setbuf.dir/setbuf.cpp.o
[97/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.setvbuf.dir/setvbuf.cpp.o
[98/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.sprintf.dir/sprintf.cpp.o
FAILED: libc/src/stdio/CMakeFiles/libc.src.stdio.sprintf.dir/sprintf.cpp.o 
/usr/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc -isystem /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/build/libc/include -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -fdiagnostics-color -g -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -DLIBC_ERRNO_MODE=LIBC_ERRNO_MODE_DEFAULT -fpie -ffreestanding -DLIBC_FULL_BUILD -nostdlibinc -idirafter/usr/include -fno-builtin -fno-exceptions -fno-lax-vector-conversions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-rtti -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wstrict-prototypes -Wthread-safety -Wglobal-constructors -DLIBC_COPT_PUBLIC_PACKAGING -DLIBC_COPT_PRINTF_RUNTIME_DISPATCH -std=gnu++17 -MD -MT libc/src/stdio/CMakeFiles/libc.src.stdio.sprintf.dir/sprintf.cpp.o -MF libc/src/stdio/CMakeFiles/libc.src.stdio.sprintf.dir/sprintf.cpp.o.d -o libc/src/stdio/CMakeFiles/libc.src.stdio.sprintf.dir/sprintf.cpp.o -c /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/sprintf.cpp
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/sprintf.cpp:14:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/printf_main.h:14:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter.h:21:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter_atlas.h:32:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/float_dec_converter.h:17:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/float_to_string.h:17:
/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/FPUtil/dyadic_float.h:419:14: error: use of function template name with no prior declaration in function call with explicit template arguments is a C++20 extension [-Werror,-Wc++20-extensions]
      return generic_as<T, ShouldSignalExceptions>();
             ^
1 error generated.
[99/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.snprintf.dir/snprintf.cpp.o
FAILED: libc/src/stdio/CMakeFiles/libc.src.stdio.snprintf.dir/snprintf.cpp.o 
/usr/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc -isystem /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/build/libc/include -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -fdiagnostics-color -g -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -DLIBC_ERRNO_MODE=LIBC_ERRNO_MODE_DEFAULT -fpie -ffreestanding -DLIBC_FULL_BUILD -nostdlibinc -idirafter/usr/include -fno-builtin -fno-exceptions -fno-lax-vector-conversions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-rtti -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wstrict-prototypes -Wthread-safety -Wglobal-constructors -DLIBC_COPT_PUBLIC_PACKAGING -DLIBC_COPT_PRINTF_RUNTIME_DISPATCH -std=gnu++17 -MD -MT libc/src/stdio/CMakeFiles/libc.src.stdio.snprintf.dir/snprintf.cpp.o -MF libc/src/stdio/CMakeFiles/libc.src.stdio.snprintf.dir/snprintf.cpp.o.d -o libc/src/stdio/CMakeFiles/libc.src.stdio.snprintf.dir/snprintf.cpp.o -c /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/snprintf.cpp
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/snprintf.cpp:13:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/printf_main.h:14:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter.h:21:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter_atlas.h:32:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/float_dec_converter.h:17:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/float_to_string.h:17:
/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/FPUtil/dyadic_float.h:419:14: error: use of function template name with no prior declaration in function call with explicit template arguments is a C++20 extension [-Werror,-Wc++20-extensions]
      return generic_as<T, ShouldSignalExceptions>();
             ^
1 error generated.
[100/454] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.asprintf.dir/asprintf.cpp.o
FAILED: libc/src/stdio/CMakeFiles/libc.src.stdio.asprintf.dir/asprintf.cpp.o 
/usr/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc -isystem /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/build/libc/include -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -fdiagnostics-color -g -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -DLIBC_ERRNO_MODE=LIBC_ERRNO_MODE_DEFAULT -fpie -ffreestanding -DLIBC_FULL_BUILD -nostdlibinc -idirafter/usr/include -fno-builtin -fno-exceptions -fno-lax-vector-conversions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-rtti -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wstrict-prototypes -Wthread-safety -Wglobal-constructors -DLIBC_COPT_PUBLIC_PACKAGING -DLIBC_COPT_PRINTF_RUNTIME_DISPATCH -std=gnu++17 -MD -MT libc/src/stdio/CMakeFiles/libc.src.stdio.asprintf.dir/asprintf.cpp.o -MF libc/src/stdio/CMakeFiles/libc.src.stdio.asprintf.dir/asprintf.cpp.o.d -o libc/src/stdio/CMakeFiles/libc.src.stdio.asprintf.dir/asprintf.cpp.o -c /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/asprintf.cpp
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/asprintf.cpp:12:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/vasprintf_internal.h:15:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/printf_main.h:14:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter.h:21:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter_atlas.h:32:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/float_dec_converter.h:17:
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/float_to_string.h:17:
/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-fullbuild-dbg/llvm-project/libc/src/__support/FPUtil/dyadic_float.h:419:14: error: use of function template name with no prior declaration in function call with explicit template arguments is a C++20 extension [-Werror,-Wc++20-extensions]
      return generic_as<T, ShouldSignalExceptions>();
             ^
1 error generated.

```

</details>

https://github.com/llvm/llvm-project/pull/144463