[all-commits] [llvm/llvm-project] 87c016: [libc] add atof, strtof and strtod

[michaelrj-google via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 87c016078ad72c46505461e4ff8bfa04819fe7ba
      https://github.com/llvm/llvm-project/commit/87c016078ad72c46505461e4ff8bfa04819fe7ba
  Author: Michael Jones <michaelrj at google.com>
  Date:   2021-10-18 (Mon, 18 Oct 2021)

  Changed paths:
    M libc/config/linux/x86_64/entrypoints.txt
    M libc/fuzzing/stdlib/CMakeLists.txt
    A libc/fuzzing/stdlib/StringParserOutputDiff.h
    A libc/fuzzing/stdlib/atof_fuzz.cpp
    M libc/spec/stdc.td
    M libc/src/__support/CMakeLists.txt
    A libc/src/__support/detailed_powers_of_ten.h
    M libc/src/__support/high_precision_decimal.h
    A libc/src/__support/str_to_float.h
    M libc/src/stdlib/CMakeLists.txt
    A libc/src/stdlib/atof.cpp
    A libc/src/stdlib/atof.h
    A libc/src/stdlib/strtod.cpp
    A libc/src/stdlib/strtod.h
    A libc/src/stdlib/strtof.cpp
    A libc/src/stdlib/strtof.h
    M libc/test/src/__support/CMakeLists.txt
    A libc/test/src/__support/str_to_float_comparison_data.txt
    A libc/test/src/__support/str_to_float_comparison_test.cpp
    A libc/test/src/__support/str_to_float_test.cpp
    M libc/test/src/stdlib/CMakeLists.txt
    A libc/test/src/stdlib/atof_test.cpp
    A libc/test/src/stdlib/strtod_test.cpp
    A libc/test/src/stdlib/strtof_test.cpp

  Log Message:
  -----------
  [libc] add atof, strtof and strtod

Add the string to floating point conversion functions.
Long doubles aren't supported yet, but floats and doubles are. The
primary algorithm used is the Eisel-Lemire ParseNumberF64 algorithm,
with the Simple Decimal Conversion algorithm as backup.

Links for more information on the algorithms:

Number Parsing at a Gigabyte per Second, Software: Practice and
Experience 51 (8), 2021 (https://arxiv.org/abs/2101.11408)
https://nigeltao.github.io/blog/2020/eisel-lemire.html
https://nigeltao.github.io/blog/2020/parse-number-f64-simple.html

Differential Revision: https://reviews.llvm.org/D109261