[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. .clang-format
  2. .clang-tidy
  3. .editorconfig
  4. .flake8
  5. .git-blame-ignore-revs
  6. .gitattributes
  7. .gitignore
  8. .gn
  9. .vpython
  10. .ycm_extra_conf.py
  11. AUTHORS
  12. BUILD.gn
  13. CODE_OF_CONDUCT.md
  14. COMMON_OWNERS
  15. DEPS
  16. ENG_REVIEW_OWNERS
  17. INFRA_OWNERS
  18. INTL_OWNERS
  19. LICENSE
  20. LICENSE.fdlibm
  21. LICENSE.strongtalk
  22. LICENSE.v8
  23. LICENSE.valgrind
  24. MIPS_OWNERS
  25. OWNERS
  26. PPC_OWNERS
  27. PRESUBMIT.py
  28. README.md
  29. S390_OWNERS
  30. WATCHLISTS
  31. build_overrides/
  32. codereview.settings
  33. custom_deps/
  34. docs/
  35. gni/
  36. include/
  37. infra/
  38. samples/
  39. src/
  40. test/
  41. testing/
  42. third_party/
  43. tools/
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.