Noah Goldstein a6edcea211 [InstCombine] Simplify (add/sub (sub/add) (sub/add)) irrelivant of use-count ...

Added folds:
    - `(add (sub X, Y), (sub Z, X))` -> `(sub Z, Y)`
    - `(sub (add X, Y), (add X, Z))` -> `(sub Y, Z)`

The fold typically is handled in the `Reassosiate` pass, but it fails
if the inner `sub`/`add` are multi-use. Less importantly, Reassosiate
doesn't propagate flags correctly.

This patch adds the fold explicitly the InstCombine

Proofs: https://alive2.llvm.org/ce/z/p6JyRP

Closes #105866

2024-08-27 11:43:17 -07:00

110 KiB

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