[llvm] [LSR] Reuse identical casts and instructions across fixups (PR #201839)

[Timur Golubovich via llvm-commits]

timurgol007 wrote:

> There are a bunch of test changes where the loop is optimized away now, that looks very suspicious. Did you review those tests?

Hi! I carefully reviewed the X86 tests. The changes are legitimate: dead code is now being optimized away, which affects register allocation and results in a larger diff.

https://github.com/llvm/llvm-project/pull/201839