[llvm] AMDGPU: Use getMergedLocation in SILoadStoreOptimizer (PR #156396)

[Pierre van Houtryve via llvm-commits]

https://github.com/Pierre-vh commented:

Would a MIR test work to test this ? https://llvm.org/docs/MIRLangRef.html#source-locations

https://github.com/llvm/llvm-project/pull/156396