llvm/test/CodeGen/AMDGPU/asyncmark-merge-empty-other.mir

# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 6
# RUN: llc -mtriple=amdgpu12.50-amd-amdhsa -run-pass=si-insert-waitcnts -o - %s | FileCheck %s

# Regression test for mergeAsyncMarks() asserting when OtherMarks is empty.
#
# At a CFG join point where one predecessor has an ASYNCMARK (non-empty
# AsyncMarks) and the other does not (empty OtherMarks), MergeCount becomes
# min(0, N) = 0. Before the fix, seq_inclusive<unsigned>(1, 0) asserted
# Begin <= End. After the fix the function returns early when either side
# is empty.
#
# GLOBAL_LOAD_ASYNC_TO_LDS_B32 is a GFX1250 async LDS DMA instruction tracked
# via ASYNC_CNT.  isAsync() returns true for it, so the score is recorded into
# AsyncScore before ASYNCMARK pushes it onto AsyncMarks.
#
# The join block contains WAIT_ASYNCMARK 0 to consume the pending mark.
# Before the fix, mergeAsyncMarks() asserted before reaching the wait.
# After the fix the pass completes without asserting.
#
# Two patterns are tested:
#   asyncmark_in_then - ASYNCMARK in the then-successor, else-successor is sync
#   asyncmark_in_else - ASYNCMARK in the else-successor, then-successor is sync

---
# Pattern 1: ASYNCMARK in then-successor, else-successor is sync.
name:            asyncmark_in_then
tracksRegLiveness: true
machineFunctionInfo:
  occupancy:       8
body:             |
  ; CHECK-LABEL: name: asyncmark_in_then
  ; CHECK: bb.0:
  ; CHECK-NEXT:   successors: %bb.2(0x40000000), %bb.1(0x40000000)
  ; CHECK-NEXT:   liveins: $sgpr0, $sgpr1, $vgpr0_vgpr1, $vgpr2
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT:   S_WAIT_LOADCNT_DSCNT .Loadcnt_0_Dscnt_0
  ; CHECK-NEXT:   S_WAIT_KMCNT 0
  ; CHECK-NEXT:   S_CMP_LG_U32 $sgpr0, $sgpr1, implicit-def $scc
  ; CHECK-NEXT:   S_CBRANCH_SCC1 %bb.2, implicit killed $scc
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT: bb.1:
  ; CHECK-NEXT:   successors: %bb.3(0x80000000)
  ; CHECK-NEXT:   liveins: $vgpr0_vgpr1, $vgpr2
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT:   GLOBAL_LOAD_ASYNC_TO_LDS_B32 $vgpr2, $vgpr0_vgpr1, 0, 0, implicit-def $asynccnt, implicit $exec, implicit $asynccnt :: (load (s32), addrspace 1), (store (s32), addrspace 3)
  ; CHECK-NEXT:   ASYNCMARK
  ; CHECK-NEXT:   S_BRANCH %bb.3
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT: bb.2:
  ; CHECK-NEXT:   successors: %bb.3(0x80000000)
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT:   S_BRANCH %bb.3
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT: bb.3:
  ; CHECK-NEXT:   WAIT_ASYNCMARK 0
  ; CHECK-NEXT:   S_WAIT_ASYNCCNT 0, implicit-def $asynccnt, implicit $asynccnt
  ; CHECK-NEXT:   S_ENDPGM 0
  bb.0:
    liveins: $sgpr0, $sgpr1, $vgpr0_vgpr1, $vgpr2

    S_CMP_LG_U32 $sgpr0, $sgpr1, implicit-def $scc
    S_CBRANCH_SCC1 %bb.2, implicit killed $scc

  ; then branch — issues async LDS DMA + ASYNCMARK
  bb.1:
    liveins: $vgpr0_vgpr1, $vgpr2

    GLOBAL_LOAD_ASYNC_TO_LDS_B32 $vgpr2, $vgpr0_vgpr1, 0, 0, implicit-def $asynccnt, implicit $exec, implicit $asynccnt :: (load (s32), addrspace 1), (store (s32), addrspace 3)
    ASYNCMARK
    S_BRANCH %bb.3

  ; else branch — sync path, no async operations; OtherMarks is empty at join
  bb.2:
    S_BRANCH %bb.3

  ; join — mergeAsyncMarks sees non-empty AsyncMarks (then) and empty OtherMarks (else).
  ; Before fix: assertion. After fix: returns early, no spurious wait inserted.
  bb.3:
    WAIT_ASYNCMARK 0
    S_ENDPGM 0
...
---
# Pattern 2: ASYNCMARK in else-successor, then-successor is sync.
# Mirror of asyncmark_in_then — exercises the opposite predecessor ordering.
name:            asyncmark_in_else
tracksRegLiveness: true
machineFunctionInfo:
  occupancy:       8
body:             |
  ; CHECK-LABEL: name: asyncmark_in_else
  ; CHECK: bb.0:
  ; CHECK-NEXT:   successors: %bb.2(0x40000000), %bb.1(0x40000000)
  ; CHECK-NEXT:   liveins: $sgpr0, $sgpr1, $vgpr0_vgpr1, $vgpr2
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT:   S_WAIT_LOADCNT_DSCNT .Loadcnt_0_Dscnt_0
  ; CHECK-NEXT:   S_WAIT_KMCNT 0
  ; CHECK-NEXT:   S_CMP_LG_U32 $sgpr0, $sgpr1, implicit-def $scc
  ; CHECK-NEXT:   S_CBRANCH_SCC1 %bb.2, implicit killed $scc
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT: bb.1:
  ; CHECK-NEXT:   successors: %bb.3(0x80000000)
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT:   S_BRANCH %bb.3
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT: bb.2:
  ; CHECK-NEXT:   successors: %bb.3(0x80000000)
  ; CHECK-NEXT:   liveins: $vgpr0_vgpr1, $vgpr2
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT:   GLOBAL_LOAD_ASYNC_TO_LDS_B32 $vgpr2, $vgpr0_vgpr1, 0, 0, implicit-def $asynccnt, implicit $exec, implicit $asynccnt :: (load (s32), addrspace 1), (store (s32), addrspace 3)
  ; CHECK-NEXT:   ASYNCMARK
  ; CHECK-NEXT:   S_BRANCH %bb.3
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT: bb.3:
  ; CHECK-NEXT:   WAIT_ASYNCMARK 0
  ; CHECK-NEXT:   S_WAIT_ASYNCCNT 0, implicit-def $asynccnt, implicit $asynccnt
  ; CHECK-NEXT:   S_ENDPGM 0
  bb.0:
    liveins: $sgpr0, $sgpr1, $vgpr0_vgpr1, $vgpr2

    S_CMP_LG_U32 $sgpr0, $sgpr1, implicit-def $scc
    S_CBRANCH_SCC1 %bb.2, implicit killed $scc

  ; then branch — sync path, no async operations
  bb.1:
    S_BRANCH %bb.3

  ; else branch — issues async LDS DMA + ASYNCMARK
  bb.2:
    liveins: $vgpr0_vgpr1, $vgpr2

    GLOBAL_LOAD_ASYNC_TO_LDS_B32 $vgpr2, $vgpr0_vgpr1, 0, 0, implicit-def $asynccnt, implicit $exec, implicit $asynccnt :: (load (s32), addrspace 1), (store (s32), addrspace 3)
    ASYNCMARK
    S_BRANCH %bb.3

  ; join block
  bb.3:
    WAIT_ASYNCMARK 0
    S_ENDPGM 0
...