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llvm / llvm-project / ae367028073f263c1b17faec70889fde36435c6d
commitae367028073f263c1b17faec70889fde36435c6d[log] [tgz]
authorCraig Topper <craig.topper@sifive.com>Thu Jul 24 17:27:48 2025 -0700
committerGitHub <noreply@github.com>Thu Jul 24 17:27:48 2025 -0700
tree40a5ff8f763e5db1d21995d299f1928ac91641b2
parent9f724d04275df1f6bfd1e4346a9c69748d04ee7f [diff]
[RISCV] Guard against out of bound shifts in expandMul. (#150464)

Spotted while reviewing #150211. If we're multiplying by -3 in i32
MulAmt contains 4,294,967,293 since we zero extend to uint64_t. Adding 3
to this gives 0x100000000 which is a power of 2 and the log2 of that is
32, but we can't shift left by 32 in an i32.

Detect this case and skip the transform. We could use 0, but we don't
handle the case for i64 so this seemed more consistent.

Normally we don't hit this case because decomposeMulByConstant handles
it, but that's disabled by Xqciac. And after #150211 the code in
expandMul is now unreachable for this case.
1 file changed
tree: 40a5ff8f763e5db1d21995d299f1928ac91641b2
  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. libunwind/
  16. lld/
  17. lldb/
  18. llvm/
  19. llvm-libgcc/
  20. mlir/
  21. offload/
  22. openmp/
  23. polly/
  24. runtimes/
  25. third-party/
  26. utils/
  27. .clang-format
  28. .clang-format-ignore
  29. .clang-tidy
  30. .git-blame-ignore-revs
  31. .gitattributes
  32. .gitignore
  33. .mailmap
  34. CODE_OF_CONDUCT.md
  35. CONTRIBUTING.md
  36. LICENSE.TXT
  37. pyproject.toml
  38. README.md
  39. SECURITY.md
README.md

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