[clang] [llvm] [InstCombine] Infer nuw for gep inbounds from base of object (PR #119225)

[via llvm-commits]

serge-sans-paille wrote:

Hey @nikic,
I've bisected the failures from this buildbot:
    https://lab.llvm.org/buildbot/#/builders/199/builds/57
down to this commit.

The reproducer is unfortunately not pleasant:
get a stage-2 build of clang then run the llvm-test suite. This reproducibility chokes on `SingleSource/Benchmarks/CoyoteBench/huffbench.test`, as can be seen on the buildbot log.

https://github.com/llvm/llvm-project/pull/119225