[llvm-branch-commits] [llvm] PeepholeOpt: Avoid double map lookup (PR #124531)

[Kazu Hirata via llvm-branch-commits]

https://github.com/kazutakahirata approved this pull request.

LGTM.  See a comment above about `const &`.

https://github.com/llvm/llvm-project/pull/124531