[clang] [llvm] [InstCombine] Strip leading zero indices from GEP (PR #155415)

[Nikita Popov via llvm-commits]

nikic wrote:

> This is the same code that triggered https://github.com/llvm/llvm-project/issues/143908 but that reproducer does not change with or without this patch.

The root cause here is the same. This change just ends up unrolling additional cases and triggers the same underlying problem with address calculations being unprofitably hoisted out of a loop and spilled. I left a comment on that issue.

https://github.com/llvm/llvm-project/pull/155415