[libc-commits] [libc] [libc][stdfix] Implement fixed point `countlsfx` functions in llvm-libc (PR #125356)

Fri Feb 7 11:06:04 PST 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `libc-riscv32-qemu-yocto-fullbuild-dbg` running on `rv32gc-qemu-system` while building `libc` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/196/builds/4704

<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)
...
[45/72] Generating header strings.h from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/runtimes/../libc/include/strings.yaml
[46/72] Generating header features.h from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/runtimes/../libc/include/features.yaml
[47/72] Generating header stdbit.h from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/runtimes/../libc/include/stdbit.yaml
[48/72] Generating header termios.h from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/runtimes/../libc/include/termios.yaml
[49/61] Generating header sys/wait.h from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/runtimes/../libc/include/sys/wait.yaml
[50/58] Generating header uchar.h from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/runtimes/../libc/include/uchar.yaml
[51/58] Generating header complex.h from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/runtimes/../libc/include/complex.yaml
[52/58] Generating header stdfix.h from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/runtimes/../libc/include/stdfix.yaml
[53/58] Generating header math.h from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/runtimes/../libc/include/math.yaml
[54/58] Building CXX object libc/src/stdio/printf_core/CMakeFiles/libc.src.stdio.printf_core.converter.dir/converter.cpp.o
FAILED: libc/src/stdio/printf_core/CMakeFiles/libc.src.stdio.printf_core.converter.dir/converter.cpp.o 
/usr/local/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc -isystem /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/build/libc/include -mabi=ilp32d -march=rv32imafdc --target=riscv32-unknown-linux-gnu --sysroot=/opt/riscv/sysroot --gcc-toolchain=/opt/riscv -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 -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -g -std=gnu++17 --target=riscv32-unknown-linux-gnu -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -fpie -ffreestanding -DLIBC_FULL_BUILD -nostdlibinc -idirafter=/usr/include -ffixed-point -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 -MD -MT libc/src/stdio/printf_core/CMakeFiles/libc.src.stdio.printf_core.converter.dir/converter.cpp.o -MF libc/src/stdio/printf_core/CMakeFiles/libc.src.stdio.printf_core.converter.dir/converter.cpp.o.d -o libc/src/stdio/printf_core/CMakeFiles/libc.src.stdio.printf_core.converter.dir/converter.cpp.o -c /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter.cpp
In file included from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter.cpp:20:
In file included from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter_atlas.h:40:
In file included from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/fixed_converter.h:15:
/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/fixed_point/fx_bits.h:191:9: error: use of undeclared identifier 'x'
  191 |     if (x < 0)
      |         ^
/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/fixed_point/fx_bits.h:192:7: error: use of undeclared identifier 'x'
  192 |       x = bit_not(x);
      |       ^
/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/fixed_point/fx_bits.h:192:19: error: use of undeclared identifier 'x'
  192 |       x = bit_not(x);
      |                   ^
/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/fixed_point/fx_bits.h:195:31: error: use of undeclared identifier 'x'
  195 |   BitType value_bits = FXBits(x)::get_bits();
      |                               ^
/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/fixed_point/fx_bits.h:195:33: error: expected ';' at end of declaration
  195 |   BitType value_bits = FXBits(x)::get_bits();
      |                                 ^
      |                                 ;
/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/fixed_point/fx_bits.h:182:11: error: unused parameter 'f' [-Werror,-Wunused-parameter]
  182 | countls(T f) {
      |           ^
In file included from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter.cpp:9:
In file included from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/converter.h:13:
In file included from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/stdio/printf_core/core_structs.h:16:
In file included from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/FPUtil/FPBits.h:21:
In file included from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/libc_assert.h:26:
In file included from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/integer_to_string.h:70:
In file included from /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/big_int.h:22:
/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/math_extras.h:28:34: error: shift count >= width of type [-Werror,-Wshift-count-overflow]
   28 |   return count == 0 ? 0 : (T(-1) >> (T_BITS - count));
      |                                  ^  ~~~~~~~~~~~~~~~~
/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/fixed_point/fx_bits.h:49:7: note: in instantiation of function template specialization '__llvm_libc_20_0_0_git::mask_trailing_ones<unsigned int, 0U>' requested here
   49 |       mask_trailing_ones<StorageType, fx_rep::INTEGRAL_LEN>()
      |       ^
/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/src/__support/fixed_point/fx_bits.h:81:21: note: in instantiation of static data member '__llvm_libc_20_0_0_git::fixed_point::FXBits<long _Fract>::INTEGRAL_MASK' requested here
   81 |     return (value & INTEGRAL_MASK) >> INTEGRAL_OFFSET;

```

</details>

https://github.com/llvm/llvm-project/pull/125356