[llvm] [DAGCombiner] ignore loads when finding store in store forwarding optimization (PR #87465)

[Nikita Popov via llvm-commits]

nikic wrote:

I tested the compile-time impact of this change, and there doesn't appear to be a statistically significant change in either direction (https://llvm-compile-time-tracker.com/compare.php?from=91189afef5fb887699da88e0ed46bdf3421d4bce&to=f9bd04be046b38822b1eba2b84fe2847d5be3a41&stat=instructions:u).

https://github.com/llvm/llvm-project/pull/87465