[AArch64][GlobalISel] Do no skip zext in getTestBitReg. (#177991)

We can, when attempting to lower to tbz, skip a zext that is then not
accounted for elsewhere. The attached test ends up with a tbz from an
extract that then does not properly zext the value extracted from the
vector. This patch fixes that by only looking through a G_ZEXT if the
bit checked is in the low part of the value, lining up the code with the
comment.

Fixes #173895

(cherry picked from commit 0321f3eeee5cceddc2541046ee155863f5f59585)
4 files changed
tree: b976d6a2c1d253772f559adb5607413ef6c1c626
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. flang-rt/
  11. libc/
  12. libclc/
  13. libcxx/
  14. libcxxabi/
  15. libsycl/
  16. libunwind/
  17. lld/
  18. lldb/
  19. llvm/
  20. llvm-libgcc/
  21. mlir/
  22. offload/
  23. openmp/
  24. orc-rt/
  25. polly/
  26. runtimes/
  27. third-party/
  28. utils/
  29. .clang-format
  30. .clang-format-ignore
  31. .clang-tidy
  32. .git-blame-ignore-revs
  33. .gitattributes
  34. .gitignore
  35. .mailmap
  36. CODE_OF_CONDUCT.md
  37. CONTRIBUTING.md
  38. LICENSE.TXT
  39. pyproject.toml
  40. README.md
  41. SECURITY.md
README.md

The LLVM Compiler Infrastructure

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