llvm-project/llvm/test/CodeGen/AMDGPU/control-flow-fastregalloc.ll

; RUN: llc -O0 -mtriple=amdgcn--amdhsa -march=amdgcn -amdgpu-spill-sgpr-to-vgpr=0 -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=VMEM -check-prefix=GCN %s
; RUN: llc -O0 -mtriple=amdgcn--amdhsa -march=amdgcn -amdgpu-spill-sgpr-to-vgpr=1 -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=VGPR -check-prefix=GCN %s

; Verify registers used for tracking exec mask changes when all
; registers are spilled at the end of the block. The SGPR spill
; placement relative to the exec modifications are important.

; FIXME: This checks with SGPR to VGPR spilling disabled, but this may
; not work correctly in cases where no workitems take a branch.


; GCN-LABEL: {{^}}divergent_if_endif:
; VGPR: workitem_private_segment_byte_size = 12{{$}}


; GCN: {{^}}; %bb.0:
; GCN: s_mov_b32 m0, -1
; GCN: ds_read_b32 [[LOAD0:v[0-9]+]]

; GCN: v_cmp_eq_u32_e64 [[CMP0:s\[[0-9]+:[0-9]\]]], s{{[0-9]+}}, v0
; GCN: s_mov_b64 s{{\[}}[[SAVEEXEC_LO:[0-9]+]]:[[SAVEEXEC_HI:[0-9]+]]{{\]}}, exec
; GCN: s_and_b64 s{{\[}}[[ANDEXEC_LO:[0-9]+]]:[[ANDEXEC_HI:[0-9]+]]{{\]}}, s{{\[}}[[SAVEEXEC_LO]]:[[SAVEEXEC_HI]]{{\]}}, [[CMP0]]

; Spill load
; GCN: buffer_store_dword [[LOAD0]], off, s[0:3], 0 offset:[[LOAD0_OFFSET:[0-9]+]] ; 4-byte Folded Spill

; Spill saved exec
; VGPR: v_writelane_b32 [[SPILL_VGPR:v[0-9]+]], s[[SAVEEXEC_LO]], [[SAVEEXEC_LO_LANE:[0-9]+]]
; VGPR: v_writelane_b32 [[SPILL_VGPR]], s[[SAVEEXEC_HI]], [[SAVEEXEC_HI_LANE:[0-9]+]]

; VMEM: v_writelane_b32 v[[V_SAVEEXEC:[0-9]+]], s[[SAVEEXEC_LO]], 0
; VMEM: v_writelane_b32 v[[V_SAVEEXEC]], s[[SAVEEXEC_HI]], 1
; VMEM: buffer_store_dword v[[V_SAVEEXEC]], off, s[0:3], 0 offset:20 ; 4-byte Folded Spill

; GCN: s_mov_b64 exec, s{{\[}}[[ANDEXEC_LO]]:[[ANDEXEC_HI]]{{\]}}

; GCN: s_cbranch_execz [[ENDIF:BB[0-9]+_[0-9]+]]

; GCN: ; %bb.{{[0-9]+}}: ; %if
; GCN: s_mov_b32 m0, -1
; GCN: ds_read_b32 [[LOAD1:v[0-9]+]]
; GCN: buffer_load_dword [[RELOAD_LOAD0:v[0-9]+]], off, s[0:3], 0 offset:[[LOAD0_OFFSET]] ; 4-byte Folded Reload
; GCN: s_waitcnt vmcnt(0) lgkmcnt(0)


; Spill val register
; GCN: v_add_i32_e32 [[VAL:v[0-9]+]], vcc, [[LOAD1]], [[RELOAD_LOAD0]]
; GCN: buffer_store_dword [[VAL]], off, s[0:3], 0 offset:[[VAL_OFFSET:[0-9]+]] ; 4-byte Folded Spill

; VMEM: [[ENDIF]]:

; Reload and restore exec mask
; VGPR: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_LO:[0-9]+]], [[SPILL_VGPR]], [[SAVEEXEC_LO_LANE]]
; VGPR: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_HI:[0-9]+]], [[SPILL_VGPR]], [[SAVEEXEC_HI_LANE]]



; VMEM: buffer_load_dword v[[V_RELOAD_SAVEEXEC:[0-9]+]], off, s[0:3], 0 offset:20 ; 4-byte Folded Reload
; VMEM: s_waitcnt vmcnt(0)
; VMEM: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_LO:[0-9]+]], v[[V_RELOAD_SAVEEXEC]], 0
; VMEM: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_HI:[0-9]+]], v[[V_RELOAD_SAVEEXEC]], 1

; GCN: s_or_b64 exec, exec, s{{\[}}[[S_RELOAD_SAVEEXEC_LO]]:[[S_RELOAD_SAVEEXEC_HI]]{{\]}}

; Restore val
; GCN: buffer_load_dword [[RELOAD_VAL:v[0-9]+]], off, s[0:3], 0 offset:[[VAL_OFFSET]] ; 4-byte Folded Reload

; GCN: flat_store_dword v{{\[[0-9]+:[0-9]+\]}}, [[RELOAD_VAL]]
define amdgpu_kernel void @divergent_if_endif(i32 addrspace(1)* %out) #0 {
entry:
  %tid = call i32 @llvm.amdgcn.workitem.id.x()
  %load0 = load volatile i32, i32 addrspace(3)* undef
  %cmp0 = icmp eq i32 %tid, 0
  br i1 %cmp0, label %if, label %endif

if:
  %load1 = load volatile i32, i32 addrspace(3)* undef
  %val = add i32 %load0, %load1
  br label %endif

endif:
  %tmp4 = phi i32 [ %val, %if ], [ 0, %entry ]
  store i32 %tmp4, i32 addrspace(1)* %out
  ret void
}

; GCN-LABEL: {{^}}divergent_loop:
; VGPR: workitem_private_segment_byte_size = 16{{$}}

; GCN: {{^}}; %bb.0:

; GCN: s_mov_b32 m0, -1
; GCN: ds_read_b32 [[LOAD0:v[0-9]+]]

; GCN: v_cmp_eq_u32_e64 [[CMP0:s\[[0-9]+:[0-9]\]]], s{{[0-9]+}}, v0

; GCN: s_mov_b64 s{{\[}}[[SAVEEXEC_LO:[0-9]+]]:[[SAVEEXEC_HI:[0-9]+]]{{\]}}, exec
; GCN: s_and_b64 s{{\[}}[[ANDEXEC_LO:[0-9]+]]:[[ANDEXEC_HI:[0-9]+]]{{\]}}, s{{\[}}[[SAVEEXEC_LO:[0-9]+]]:[[SAVEEXEC_HI:[0-9]+]]{{\]}}, [[CMP0]]

; Spill load
; GCN: buffer_store_dword [[LOAD0]], off, s[0:3], 0 offset:[[LOAD0_OFFSET:[0-9]+]] ; 4-byte Folded Spill

; Spill saved exec
; VGPR: v_writelane_b32 [[SPILL_VGPR:v[0-9]+]], s[[SAVEEXEC_LO]], [[SAVEEXEC_LO_LANE:[0-9]+]]
; VGPR: v_writelane_b32 [[SPILL_VGPR]], s[[SAVEEXEC_HI]], [[SAVEEXEC_HI_LANE:[0-9]+]]


; VMEM: v_writelane_b32 v[[V_SAVEEXEC:[0-9]+]], s[[SAVEEXEC_LO]], 0
; VMEM: v_writelane_b32 v[[V_SAVEEXEC]], s[[SAVEEXEC_HI]], 1
; VMEM: buffer_store_dword v[[V_SAVEEXEC]], off, s[0:3], 0 offset:24 ; 4-byte Folded Spill

; GCN: s_mov_b64 exec, s{{\[}}[[ANDEXEC_LO]]:[[ANDEXEC_HI]]{{\]}}

; GCN-NEXT: s_cbranch_execz [[END:BB[0-9]+_[0-9]+]]


; GCN: [[LOOP:BB[0-9]+_[0-9]+]]:
; GCN: buffer_load_dword v[[VAL_LOOP_RELOAD:[0-9]+]], off, s[0:3], 0 offset:[[LOAD0_OFFSET]] ; 4-byte Folded Reload
; GCN: v_subrev_i32_e32 [[VAL_LOOP:v[0-9]+]], vcc, v{{[0-9]+}}, v[[VAL_LOOP_RELOAD]]
; GCN: s_cmp_lg_u32
; GCN: buffer_store_dword [[VAL_LOOP]], off, s[0:3], 0 offset:{{[0-9]+}} ; 4-byte Folded Spill
; GCN-NEXT: s_cbranch_scc1 [[LOOP]]

; GCN: buffer_store_dword [[VAL_LOOP]], off, s[0:3], 0 offset:[[VAL_SUB_OFFSET:[0-9]+]] ; 4-byte Folded Spill

; GCN: [[END]]:
; VGPR: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_LO:[0-9]+]], [[SPILL_VGPR]], [[SAVEEXEC_LO_LANE]]
; VGPR: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_HI:[0-9]+]], [[SPILL_VGPR]], [[SAVEEXEC_HI_LANE]]

; VMEM: buffer_load_dword v[[V_RELOAD_SAVEEXEC:[0-9]+]], off, s[0:3], 0 offset:24 ; 4-byte Folded Reload
; VMEM: s_waitcnt vmcnt(0)
; VMEM: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_LO:[0-9]+]], v[[V_RELOAD_SAVEEXEC]], 0
; VMEM: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_HI:[0-9]+]], v[[V_RELOAD_SAVEEXEC]], 1

; GCN: s_or_b64 exec, exec, s{{\[}}[[S_RELOAD_SAVEEXEC_LO]]:[[S_RELOAD_SAVEEXEC_HI]]{{\]}}
; GCN: buffer_load_dword v[[VAL_END:[0-9]+]], off, s[0:3], 0 offset:[[VAL_SUB_OFFSET]] ; 4-byte Folded Reload

; GCN: flat_store_dword v{{\[[0-9]+:[0-9]+\]}}, v[[VAL_END]]
define amdgpu_kernel void @divergent_loop(i32 addrspace(1)* %out) #0 {
entry:
  %tid = call i32 @llvm.amdgcn.workitem.id.x()
  %load0 = load volatile i32, i32 addrspace(3)* undef
  %cmp0 = icmp eq i32 %tid, 0
  br i1 %cmp0, label %loop, label %end

loop:
  %i = phi i32 [ %i.inc, %loop ], [ 0, %entry ]
  %val = phi i32 [ %val.sub, %loop ], [ %load0, %entry ]
  %load1 = load volatile i32, i32 addrspace(3)* undef
  %i.inc = add i32 %i, 1
  %val.sub = sub i32 %val, %load1
  %cmp1 = icmp ne i32 %i, 256
  br i1 %cmp1, label %loop, label %end

end:
  %tmp4 = phi i32 [ %val.sub, %loop ], [ 0, %entry ]
  store i32 %tmp4, i32 addrspace(1)* %out
  ret void
}

; GCN-LABEL: {{^}}divergent_if_else_endif:
; GCN: {{^}}; %bb.0:

; GCN: s_mov_b32 m0, -1
; GCN: ds_read_b32 [[LOAD0:v[0-9]+]]

; GCN: s_mov_b32 [[ZERO:s[0-9]+]], 0
; GCN: v_cmp_ne_u32_e64 [[CMP0:s\[[0-9]+:[0-9]\]]], [[ZERO]], v0

; GCN: s_mov_b64 s{{\[}}[[SAVEEXEC_LO:[0-9]+]]:[[SAVEEXEC_HI:[0-9]+]]{{\]}}, exec
; GCN: s_and_b64 s{{\[}}[[ANDEXEC_LO:[0-9]+]]:[[ANDEXEC_HI:[0-9]+]]{{\]}}, s{{\[}}[[SAVEEXEC_LO:[0-9]+]]:[[SAVEEXEC_HI:[0-9]+]]{{\]}}, [[CMP0]]
; GCN: s_xor_b64 s{{\[}}[[SAVEEXEC_LO]]:[[SAVEEXEC_HI]]{{\]}}, s{{\[}}[[ANDEXEC_LO]]:[[ANDEXEC_HI]]{{\]}}, s{{\[}}[[SAVEEXEC_LO]]:[[SAVEEXEC_HI]]{{\]}}

; Spill load
; GCN: buffer_store_dword [[LOAD0]], off, s[0:3], 0 offset:[[LOAD0_OFFSET:[0-9]+]] ; 4-byte Folded Spill

; Spill saved exec
; VGPR: v_writelane_b32 [[SPILL_VGPR:v[0-9]+]], s[[SAVEEXEC_LO]], [[SAVEEXEC_LO_LANE:[0-9]+]]
; VGPR: v_writelane_b32 [[SPILL_VGPR]], s[[SAVEEXEC_HI]], [[SAVEEXEC_HI_LANE:[0-9]+]]

; VMEM: v_writelane_b32 v[[V_SAVEEXEC:[0-9]+]], s[[SAVEEXEC_LO]], 0
; VMEM: v_writelane_b32 v[[V_SAVEEXEC]], s[[SAVEEXEC_HI]], 1
; VMEM: buffer_store_dword v[[V_SAVEEXEC]], off, s[0:3], 0 offset:[[SAVEEXEC_OFFSET:[0-9]+]] ; 4-byte Folded Spill

; GCN: s_mov_b64 exec, [[CMP0]]

; FIXME: It makes no sense to put this skip here
; GCN: s_cbranch_execz [[FLOW:BB[0-9]+_[0-9]+]]
; GCN-NEXT: s_branch [[ELSE:BB[0-9]+_[0-9]+]]

; GCN: [[FLOW]]: ; %Flow
; VGPR: v_readlane_b32 s[[FLOW_S_RELOAD_SAVEEXEC_LO:[0-9]+]], [[SPILL_VGPR]], [[SAVEEXEC_LO_LANE]]
; VGPR: v_readlane_b32 s[[FLOW_S_RELOAD_SAVEEXEC_HI:[0-9]+]], [[SPILL_VGPR]], [[SAVEEXEC_HI_LANE]]


; VMEM: buffer_load_dword v[[FLOW_V_RELOAD_SAVEEXEC:[0-9]+]], off, s[0:3], 0 offset:[[SAVEEXEC_OFFSET]]
; VMEM: s_waitcnt vmcnt(0)
; VMEM: v_readlane_b32 s[[FLOW_S_RELOAD_SAVEEXEC_LO:[0-9]+]], v[[FLOW_V_RELOAD_SAVEEXEC]], 0
; VMEM: v_readlane_b32 s[[FLOW_S_RELOAD_SAVEEXEC_HI:[0-9]+]], v[[FLOW_V_RELOAD_SAVEEXEC]], 1

; GCN: s_or_saveexec_b64 s{{\[}}[[FLOW_S_RELOAD_SAVEEXEC_LO]]:[[FLOW_S_RELOAD_SAVEEXEC_HI]]{{\]}}, s{{\[}}[[FLOW_S_RELOAD_SAVEEXEC_LO]]:[[FLOW_S_RELOAD_SAVEEXEC_HI]]{{\]}}

; Regular spill value restored after exec modification
; GCN: buffer_load_dword [[FLOW_VAL:v[0-9]+]], off, s[0:3], 0 offset:[[FLOW_VAL_OFFSET:[0-9]+]] ; 4-byte Folded Reload


; Spill saved exec
; VGPR: v_writelane_b32 [[SPILL_VGPR]], s[[FLOW_S_RELOAD_SAVEEXEC_LO]], [[FLOW_SAVEEXEC_LO_LANE:[0-9]+]]
; VGPR: v_writelane_b32 [[SPILL_VGPR]], s[[FLOW_S_RELOAD_SAVEEXEC_HI]], [[FLOW_SAVEEXEC_HI_LANE:[0-9]+]]


; VMEM: v_writelane_b32 v[[FLOW_V_SAVEEXEC:[0-9]+]], s[[FLOW_S_RELOAD_SAVEEXEC_LO]], 0
; VMEM: v_writelane_b32 v[[FLOW_V_SAVEEXEC]], s[[FLOW_S_RELOAD_SAVEEXEC_HI]], 1
; VMEM: buffer_store_dword v[[FLOW_V_SAVEEXEC]], off, s[0:3], 0 offset:[[FLOW_SAVEEXEC_OFFSET:[0-9]+]] ; 4-byte Folded Spill

; GCN: buffer_store_dword [[FLOW_VAL]], off, s[0:3], 0 offset:[[RESULT_OFFSET:[0-9]+]] ; 4-byte Folded Spill
; GCN: s_xor_b64 exec, exec, s{{\[}}[[FLOW_S_RELOAD_SAVEEXEC_LO]]:[[FLOW_S_RELOAD_SAVEEXEC_HI]]{{\]}}
; GCN-NEXT: s_cbranch_execz [[ENDIF:BB[0-9]+_[0-9]+]]


; GCN: ; %bb.{{[0-9]+}}: ; %if
; GCN: ds_read_b32
; GCN: buffer_load_dword v[[LOAD0_RELOAD:[0-9]+]], off, s[0:3], 0 offset:[[LOAD0_OFFSET]] ; 4-byte Folded Reload
; GCN: v_add_i32_e32 [[ADD:v[0-9]+]], vcc, v{{[0-9]+}}, v[[LOAD0_RELOAD]]
; GCN: buffer_store_dword [[ADD]], off, s[0:3], 0 offset:[[RESULT_OFFSET]] ; 4-byte Folded Spill
; GCN-NEXT: s_branch [[ENDIF:BB[0-9]+_[0-9]+]]

; GCN: [[ELSE]]: ; %else
; GCN: buffer_load_dword v[[LOAD0_RELOAD:[0-9]+]], off, s[0:3], 0 offset:[[LOAD0_OFFSET]] ; 4-byte Folded Reload
; GCN: v_subrev_i32_e32 [[SUB:v[0-9]+]], vcc, v{{[0-9]+}}, v[[LOAD0_RELOAD]]
; GCN: buffer_store_dword [[ADD]], off, s[0:3], 0 offset:[[FLOW_RESULT_OFFSET:[0-9]+]] ; 4-byte Folded Spill
; GCN-NEXT: s_branch [[FLOW]]

; GCN: [[ENDIF]]:
; VGPR: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_LO:[0-9]+]], [[SPILL_VGPR]], [[FLOW_SAVEEXEC_LO_LANE]]
; VGPR: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_HI:[0-9]+]], [[SPILL_VGPR]], [[FLOW_SAVEEXEC_HI_LANE]]


; VMEM: buffer_load_dword v[[V_RELOAD_SAVEEXEC:[0-9]+]], off, s[0:3], 0 offset:[[FLOW_SAVEEXEC_OFFSET]] ; 4-byte Folded Reload
; VMEM: s_waitcnt vmcnt(0)
; VMEM: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_LO:[0-9]+]], v[[V_RELOAD_SAVEEXEC]], 0
; VMEM: v_readlane_b32 s[[S_RELOAD_SAVEEXEC_HI:[0-9]+]], v[[V_RELOAD_SAVEEXEC]], 1

; GCN: s_or_b64 exec, exec, s{{\[}}[[S_RELOAD_SAVEEXEC_LO]]:[[S_RELOAD_SAVEEXEC_HI]]{{\]}}

; GCN: buffer_load_dword v[[RESULT:[0-9]+]], off, s[0:3], 0 offset:[[RESULT_OFFSET]] ; 4-byte Folded Reload
; GCN: flat_store_dword v{{\[[0-9]+:[0-9]+\]}}, v[[RESULT]]
define amdgpu_kernel void @divergent_if_else_endif(i32 addrspace(1)* %out) #0 {
entry:
  %tid = call i32 @llvm.amdgcn.workitem.id.x()
  %load0 = load volatile i32, i32 addrspace(3)* undef
  %cmp0 = icmp eq i32 %tid, 0
  br i1 %cmp0, label %if, label %else

if:
  %load1 = load volatile i32, i32 addrspace(3)* undef
  %val0 = add i32 %load0, %load1
  br label %endif

else:
  %load2 = load volatile i32, i32 addrspace(3)* undef
  %val1 = sub i32 %load0, %load2
  br label %endif

endif:
  %result = phi i32 [ %val0, %if ], [ %val1, %else ]
  store i32 %result, i32 addrspace(1)* %out
  ret void
}

declare i32 @llvm.amdgcn.workitem.id.x() #1

attributes #0 = { nounwind }
attributes #1 = { nounwind readnone }