[PATCH] D60294: [DAGCombiner] [CodeGenPrepare] WIP/RFC Splitting large offsets from base addresses

[Luís Marques via Phabricator via llvm-commits]

luismarques added a comment.

In D60294#1456609 <https://reviews.llvm.org/D60294#1456609>, @efriedma wrote:

> Should we care about the number of uses of N0 here?  It should generally be "safe" to reassociate in cases where it only has one use.


Let's say we are doing `*(x + 0x10000 + 2)` and we don't use `x + 0x10000` anywhere else (that's the `N0`, right?).  In an arch like RISC-V if we want to add `0x10002` to `x` that takes two instructions to materialize the constant, while `0x10000` only takes one. We can avoid that second instruction by folding the +2 into the load/store. Am I thinking about this wrong?


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