[llvm] [InstCombine] Remove one-use restriction on icmp of gep fold (PR #76730)

[Nikita Popov via llvm-commits]

nikic wrote:

Looks like `@_ZNK4llvm3opt7ArgList10getLastArgIJN5clang6driver7options2IDEEEEPNS0_3ArgEDpT_` no longer gets inlined. Probably the different representation pushed this just over an inlining threshold. As inlining this function probably isn't actually worthwhile, this seems fine.

The final version of the function is getting additional simplification relative to the baseline -- one of the pointer comparisons now gets optimized away.

https://github.com/llvm/llvm-project/pull/76730