[flang] [lldb] [libcxx] [libc] [llvm] [clang] [libunwind] [clang-tools-extra] [compiler-rt] [lld] [X86] Use RORX over SHR imm (PR #77964)

[Bryce Wilson via cfe-commits]

Bryce-MW wrote:

I spent some time trying out something much more complex: starting at the user of flags that has other inputs (ADC, SBB, CMOVcc are the main ones), trace back the non-flags inputs to see if the node producing the flags inputs is along their paths then check the path from there to the flags user for instructions that produce flags and check if they can be rewritten. This works, but I felt like it was too complicated, , isn't particularly efficient, and didn't seem to improve any code that I tested with.

I have some ideas for future PRs related to avoiding flags spilling so if I come up with a better way to do this kind of thing in the future, I can always come back to it.

https://github.com/llvm/llvm-project/pull/77964