[flang][runtime] Handle Fw.0 case that needs to round up to 1.0 (#74384)

A tricky case in Fw.d output editing is when the value needs to be
rounded either to a signed zero or away from zero to a power of ten
(1.0, 0.1, &c.). A bug report for LLVM on GitHub (#74274) exposed a bug
in this code in the case of Fw.0 editing where a value just over 0.5 was
rounded incorrectly to 0 rather than 1 when no fractional digits were
requested.

Rework that algorithm a little, ensuring that the initial
binary->decimal conversion produces at least one digit, and coping
correctly with the rounding of an exact 0.5 value for Fw.0 editing
(rounding it to the nearest even decimal, namely 0, following
near-universal compiler-dependent behavior in other Fortrans).

Fixes https://github.com/llvm/llvm-project/issues/74274.
2 files changed
tree: 949b897e3c0ac40133c290f6280c5b0a77054c68
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. libc/
  11. libclc/
  12. libcxx/
  13. libcxxabi/
  14. libunwind/
  15. lld/
  16. lldb/
  17. llvm/
  18. llvm-libgcc/
  19. mlir/
  20. openmp/
  21. polly/
  22. pstl/
  23. runtimes/
  24. third-party/
  25. utils/
  26. .arcconfig
  27. .arclint
  28. .clang-format
  29. .clang-tidy
  30. .git-blame-ignore-revs
  31. .gitignore
  32. .mailmap
  33. CODE_OF_CONDUCT.md
  34. CONTRIBUTING.md
  35. LICENSE.TXT
  36. README.md
  37. SECURITY.md
README.md

The LLVM Compiler Infrastructure

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Welcome to the LLVM project!

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The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.

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