llvm/test/CodeGen/AArch64/framelayout-scavengingslot-stack-hazard.mir

# RUN: llc -mtriple=aarch64-none-linux-gnu -aarch64-stack-hazard-size=1024 -run-pass=prologepilog %s -o - | FileCheck %s
--- |

  define void @stack_hazard_streaming_compat() "aarch64_pstate_sm_compatible" { entry: unreachable }
  define void @stack_hazard_streaming_compat_emergency_spill_slot() "aarch64_pstate_sm_compatible" { entry: unreachable }

...

# +------------------+
# | GPR callee-saves |
# +------------------+ <- FP
# | <hazard padding> |
# +------------------+
# | FPR locals       |
# | %stack.1         |
# +------------------+
# | <hazard padding> |
# +------------------+
# | GPR locals       |
# | %stack.2         |
# | <emergency spill>|
# +------------------+ <- BP
# | <VLA>            |
# +------------------+ <- SP (can't be used due to VLA)

# In this case without the base pointer we'd need the emergency spill slot to
# access both %stack.1 and %stack.2. With the base pointer we can reach both
# without spilling.

name: stack_hazard_streaming_compat
# CHECK-LABEL: name: stack_hazard_streaming_compat
# CHECK: bb.0:
# CHECK:      STRDui $d0, $x19, 131
# CHECK-NEXT: STRXui $x0, $x19, 1
# CHECK: bb.1:
tracksRegLiveness: true
frameInfo:
  isFrameAddressTaken: true
stack:
  - { id: 0, type: variable-sized,  alignment: 1 }
  - { id: 1, size: 8, alignment: 8 }
  - { id: 2, size: 8, alignment: 8 }
body: |
  bb.0:
    liveins: $x0, $x8, $d0
    $x9 = LDRXui $x0, 0 :: (load (s64))
    STRDui $d0, %stack.1, 0 :: (store (s64) into %stack.1)
    STRXui $x0, %stack.2, 0 :: (store (s64) into %stack.2)
    B %bb.1
  bb.1:
    liveins: $x1, $x2, $x3, $x4, $x5, $x6, $x7, $x8, $x9, $x10, $x11, $x12, $x13, $x14, $x15, $x16, $x17, $x18, $x19, $x20, $x21, $x22, $x23, $x24, $x25, $x26, $x27, $x28, $lr
    RET_ReallyLR implicit $x19, implicit $x20, implicit $x21, implicit $x22, implicit $x23, implicit $x24, implicit $x25, implicit $x26, implicit $x27, implicit $x28, implicit $lr
...
---
# +------------------+
# | GPR callee-saves |
# +------------------+ <- FP
# | <hazard padding> |
# +------------------+
# | FPR locals       |
# | %stack.1         |
# +------------------+
# | <hazard padding> |
# +------------------+
# | GPR locals       |
# | %stack.2         | (very large)
# | <emergency spill>|
# +------------------+ <- BP
# | <VLA>            |
# +------------------+ <- SP (can't be used due to VLA)

# In this case we need to use the emergency spill slot to access %stack.1 as it
# is too far from the frame pointer and the base pointer to directly address.
# Note: This also tests that the <emergency spill> located near the SP/BP.

name: stack_hazard_streaming_compat_emergency_spill_slot
# CHECK-LABEL: name: stack_hazard_streaming_compat_emergency_spill_slot
# CHECK: bb.0:
# CHECK:      STRXui killed $[[SCRATCH:x[0-9]+]], $x19, 0
# CHECK-NEXT: $[[SCRATCH]] = ADDXri $x19, 1056, 0
# CHECK-NEXT: STRDui $d0, killed $[[SCRATCH]], 4095
# CHECK-NEXT: $[[SCRATCH]] = LDRXui $x19, 0
# CHECK: bb.1:
tracksRegLiveness: true
frameInfo:
  isFrameAddressTaken: true
stack:
  - { id: 0, type: variable-sized,  alignment: 1 }
  - { id: 1, size: 8, alignment: 8 }
  - { id: 2, size: 32761, alignment: 8 }
body: |
  bb.0:
    liveins: $x0, $x8, $d0
    $x9 = LDRXui $x0, 0 :: (load (s64))
    STRDui $d0, %stack.1, 0 :: (store (s64) into %stack.1)
    B %bb.1
  bb.1:
    liveins: $x0, $x1, $x2, $x3, $x4, $x5, $x6, $x7, $x8, $x9, $x10, $x11, $x12, $x13, $x14, $x15, $x16, $x17, $x18, $x19, $x20, $x21, $x22, $x23, $x24, $x25, $x26, $x27, $x28, $lr
    RET_ReallyLR implicit $x19, implicit $x20, implicit $x21, implicit $x22, implicit $x23, implicit $x24, implicit $x25, implicit $x26, implicit $x27, implicit $x28, implicit $lr