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llvm / llvm-project / df9e5ae5b40c4d245d904a2565e46f5b7ab9c7c8
commitdf9e5ae5b40c4d245d904a2565e46f5b7ab9c7c8[log] [tgz]
authorLuke Lau <luke@igalia.com>Wed Apr 02 21:21:52 2025 +0100
committerGitHub <noreply@github.com>Wed Apr 02 21:21:52 2025 +0100
treef4796fce1b6adefba144e26c7670a7da4b53b248
parent564e04b703dc5df062f862e32c00bf1a1716f96f [diff]
[InstCombine] Match scalable splats in m_ImmConstant (#132522)

#118806 fixed an infinite loop in FoldShiftByConstant that could occur
when the shift amount was a ConstantExpr.

However this meant that FoldShiftByConstant no longer kicked in for
scalable vectors because scalable splats are represented by
ConstantExprs.

This fixes it by allowing scalable splats of non-ConstantExprs in
m_ImmConstant, which also fixes a few other test cases where scalable
splats were being missed.

But I'm also hoping that UseConstantIntForScalableSplat will eventually
remove the need for this.

I noticed this when trying to reverse a combine on RISC-V in #132245,
and saw that the resulting vector and scalar forms were different.

---------

Co-authored-by: Yingwei Zheng <dtcxzyw@qq.com>
5 files changed
tree: f4796fce1b6adefba144e26c7670a7da4b53b248
  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. pstl/
  25. runtimes/
  26. third-party/
  27. utils/
  28. .clang-format
  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
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