[TurboFan] Loop variable analysis requires more sensitivity

Loop variable analysis doesn't recognize that the initial type of the
loop variable phi combined with the increment type may produce a NaN
result through the addition of two infinities of differing sign.

This leads to unreachable code and a SIGINT crash.

The fix is to consider this case before typing the loop variable phi,
falling back to more conservative typing if discovered.

R=neis@chromium.org

Bug: chromium:1028863
Change-Id: Ic4b5189c4c50c5bbe29e46050de630fd0673de9f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1946352
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65291}
3 files changed
tree: 8ac7a12389ceed9704bee43d8bb1afbaeee7e1f0
  1. build_overrides/
  2. custom_deps/
  3. docs/
  4. gni/
  5. include/
  6. infra/
  7. samples/
  8. src/
  9. test/
  10. testing/
  11. third_party/
  12. tools/
  13. .clang-format
  14. .clang-tidy
  15. .editorconfig
  16. .flake8
  17. .git-blame-ignore-revs
  18. .gitattributes
  19. .gitignore
  20. .gn
  21. .vpython
  22. .ycm_extra_conf.py
  23. AUTHORS
  24. BUILD.gn
  25. CODE_OF_CONDUCT.md
  26. codereview.settings
  27. COMMON_OWNERS
  28. DEPS
  29. ENG_REVIEW_OWNERS
  30. INFRA_OWNERS
  31. INTL_OWNERS
  32. LICENSE
  33. LICENSE.fdlibm
  34. LICENSE.strongtalk
  35. LICENSE.v8
  36. LICENSE.valgrind
  37. MIPS_OWNERS
  38. OWNERS
  39. PPC_OWNERS
  40. PRESUBMIT.py
  41. README.md
  42. S390_OWNERS
  43. WATCHLISTS
README.md

V8 JavaScript Engine

V8 is Google's open source JavaScript engine.

V8 implements ECMAScript as specified in ECMA-262.

V8 is written in C++ and is used in Google Chrome, the open source browser from Google.

V8 can run standalone, or can be embedded into any C++ application.

V8 Project page: https://v8.dev/docs

Getting the Code

Checkout depot tools, and run

    fetch v8

This will checkout V8 into the directory v8 and fetch all of its dependencies. To stay up to date, run

    git pull origin
    gclient sync

For fetching all branches, add the following into your remote configuration in .git/config:

    fetch = +refs/branch-heads/*:refs/remotes/branch-heads/*
    fetch = +refs/tags/*:refs/tags/*

Contributing

Please follow the instructions mentioned at v8.dev/docs/contribute.