llvm/llvm/test/CodeGen/AArch64/blr-bti-preserves-operands.mir

# RUN: llc -mtriple=aarch64-none-linux-gnu -run-pass=aarch64-expand-pseudo -o - %s | FileCheck %s

# When expanding a BLR_BTI, we should copy all the operands to the branch in the
# bundle. Otherwise we could end up using a register after the BL which was
# clobbered by the function that was called, or overwriting an argument to that
# function before we take the branch.
#
# The arguments to the call must become implicit arguments, because the branch
# only expects to get 1 explicit operand which is the branch target.

# CHECK:    BUNDLE implicit-def $lr, implicit-def $w30, implicit-def $sp, implicit-def $wsp, implicit $sp, implicit $x0, implicit $w1 {
# CHECK:      BL @_setjmp, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $x0, implicit $w1, implicit-def dead $lr, implicit $sp, implicit-def $sp
# CHECK:      HINT 36
# CHECK:    }

--- |
  define void @a() {
    ret void
  }

  declare void @_setjmp(...)
...
---
name: a
body: |
  bb.0:
    BLR_BTI @_setjmp, $x0, $w1, csr_aarch64_aapcs, implicit-def dead $lr, implicit $sp, implicit-def $sp
...