[llvm] [RISCV] Remove custom isel lowering of i64 to Zilsd load/store. (PR #169067)

[Christian Herber via llvm-commits]

christian-herber-nxp wrote:

Normalized binary size:
<img width="1912" height="892" alt="image" src="https://github.com/user-attachments/assets/546a8b82-54c3-4423-953b-5de94034c434" />

I did run the patch through embench-iot 1.0 to check for changes in code size. This is run at O0, march=rv32imb_zce_zdinx_zilsd_zclsd.

Overall, this patch has a slight negative effect, with some workloads getting better and some worse.
On EEMBC I am seeing little movement, 0.5% improvement in favor of the patch.

<img width="1349" height="609" alt="image" src="https://github.com/user-attachments/assets/0d58a4b3-0404-4754-8612-5a142798fa39" />



https://github.com/llvm/llvm-project/pull/169067