[PATCH] D126861: [RISCV] Fix missing stack pointer recover

[Kito Cheng via Phabricator via llvm-commits]

kito-cheng added a comment.

> Kito, I don't get your comment. I'd expect the CSR restores to be happening before stack adjustment.

It's too late to do stack adjustment after CSR restore by moving `fp` to `sp`, because `s0`(`fp`) is CSR.

  addi sp, s0, -32
  ld ra, 24(sp) # 8-byte Folded Reload
  ld s0, 16(sp) # 8-byte Folded Reload <----- s0 is restore here 
  ld s1, 8(sp) # 8-byte Folded Reload
  addi sp, sp, 32
  ret



> Are you saying that there's some other code which tries to insert restores in the middle of the existing stack adjustment sequence?

No, I mean signal and interrupt might raise during epilogue, and that will keep using `sp`, and adjust that in the handler, so `sp` must adjust after CSR restores.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D126861/new/

https://reviews.llvm.org/D126861