[all-commits] [llvm/llvm-project] 1fedd9: [AVR] fix interrupt stack pointer restoration

[Andrew Dona-Couch -- GitHub drop ICE via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 1fedd90cc7a8deabf7d75d3e668bd56ce9b1ffcc
      https://github.com/llvm/llvm-project/commit/1fedd90cc7a8deabf7d75d3e668bd56ce9b1ffcc
  Author: Andrew Dona-Couch <hi at andrewcou.ch>
  Date:   2020-10-01 (Thu, 01 Oct 2020)

  Changed paths:
    M llvm/lib/Target/AVR/AVRFrameLowering.cpp
    M llvm/test/CodeGen/AVR/interrupts.ll

  Log Message:
  -----------
  [AVR] fix interrupt stack pointer restoration

This patch fixes a corruption of the stack pointer and several registers in any AVR interrupt with non-empty stack frame.  Previously, the callee-saved registers were popped before restoring the stack pointer, causing the pointer math to use the wrong base value while also corrupting the caller's register.  This change fixes the code to restore the stack pointer last before exiting the interrupt service routine.

https://bugs.llvm.org/show_bug.cgi?id=47253

Reviewed By: dylanmckay

Differential Revision: https://reviews.llvm.org/D87735

Patch by Andrew Dona-Couch.