llvm-project/llvm/test/CodeGen/AMDGPU/branch-relaxation.ll

480 lines
12 KiB
LLVM

; RUN: llc -march=amdgcn -verify-machineinstrs -amdgpu-s-branch-bits=4 < %s | FileCheck -check-prefix=GCN %s
; Restrict maximum branch to between +7 and -8 dwords
; Used to emit an always 4 byte instruction. Inline asm always assumes
; each instruction is the maximum size.
declare void @llvm.amdgcn.s.sleep(i32) #0
declare i32 @llvm.amdgcn.workitem.id.x() #1
; GCN-LABEL: {{^}}uniform_conditional_max_short_forward_branch:
; GCN: s_load_dword [[CND:s[0-9]+]]
; GCN: s_cmp_eq_u32 [[CND]], 0
; GCN-NEXT: s_cbranch_scc1 [[BB3:BB[0-9]+_[0-9]+]]
; GCN-NEXT: ; BB#1: ; %bb2
; GCN-NEXT: ;;#ASMSTART
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: s_sleep 0
; GCN-NEXT: [[BB3]]: ; %bb3
; GCN: v_mov_b32_e32 [[V_CND:v[0-9]+]], [[CND]]
; GCN: buffer_store_dword [[V_CND]]
; GCN: s_endpgm
define void @uniform_conditional_max_short_forward_branch(i32 addrspace(1)* %arg, i32 %cnd) #0 {
bb:
%cmp = icmp eq i32 %cnd, 0
br i1 %cmp, label %bb3, label %bb2 ; +8 dword branch
bb2:
; 24 bytes
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
call void @llvm.amdgcn.s.sleep(i32 0)
br label %bb3
bb3:
store volatile i32 %cnd, i32 addrspace(1)* %arg
ret void
}
; GCN-LABEL: {{^}}uniform_conditional_min_long_forward_branch:
; GCN: s_load_dword [[CND:s[0-9]+]]
; GCN: s_cmp_eq_u32 [[CND]], 0
; GCN-NEXT: s_cbranch_scc0 [[LONGBB:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONG_JUMP:BB[0-9]+_[0-9]+]]: ; %bb0
; GCN-NEXT: s_getpc_b64 vcc
; GCN-NEXT: s_add_u32 vcc_lo, vcc_lo, [[ENDBB:BB[0-9]+_[0-9]+]]-([[LONG_JUMP]]+4)
; GCN-NEXT: s_addc_u32 vcc_hi, vcc_hi, 0
; GCN-NEXT: s_setpc_b64 vcc
; GCN-NEXT: [[LONGBB]]:
; GCN-NEXT: ;;#ASMSTART
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: [[ENDBB]]:
; GCN: v_mov_b32_e32 [[V_CND:v[0-9]+]], [[CND]]
; GCN: buffer_store_dword [[V_CND]]
; GCN: s_endpgm
define void @uniform_conditional_min_long_forward_branch(i32 addrspace(1)* %arg, i32 %cnd) #0 {
bb0:
%cmp = icmp eq i32 %cnd, 0
br i1 %cmp, label %bb3, label %bb2 ; +9 dword branch
bb2:
; 32 bytes
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %bb3
bb3:
store volatile i32 %cnd, i32 addrspace(1)* %arg
ret void
}
; GCN-LABEL: {{^}}uniform_conditional_min_long_forward_vcnd_branch:
; GCN: s_load_dword [[CND:s[0-9]+]]
; GCN-DAG: v_cmp_eq_f32_e64 [[CMP:s\[[0-9]+:[0-9]+\]]], [[CND]], 0
; GCN-DAG: v_mov_b32_e32 [[V_CND:v[0-9]+]], [[CND]]
; GCN: s_and_b64 vcc, exec, [[CMP]]
; GCN-NEXT: s_cbranch_vccz [[LONGBB:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONG_JUMP:BB[0-9]+_[0-9]+]]: ; %bb0
; GCN-NEXT: s_getpc_b64 vcc
; GCN-NEXT: s_add_u32 vcc_lo, vcc_lo, [[ENDBB:BB[0-9]+_[0-9]+]]-([[LONG_JUMP]]+4)
; GCN-NEXT: s_addc_u32 vcc_hi, vcc_hi, 0
; GCN-NEXT: s_setpc_b64 vcc
; GCN-NEXT: [[LONGBB]]:
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: [[ENDBB]]:
; GCN: buffer_store_dword [[V_CND]]
; GCN: s_endpgm
define void @uniform_conditional_min_long_forward_vcnd_branch(float addrspace(1)* %arg, float %cnd) #0 {
bb0:
%cmp = fcmp oeq float %cnd, 0.0
br i1 %cmp, label %bb3, label %bb2 ; + 8 dword branch
bb2:
call void asm sideeffect " ; 32 bytes
v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %bb3
bb3:
store volatile float %cnd, float addrspace(1)* %arg
ret void
}
; GCN-LABEL: {{^}}min_long_forward_vbranch:
; GCN: buffer_load_dword
; GCN: v_cmp_ne_u32_e32 vcc, 0, v{{[0-9]+}}
; GCN: s_and_saveexec_b64 [[SAVE:s\[[0-9]+:[0-9]+\]]], vcc
; GCN: s_xor_b64 [[SAVE]], exec, [[SAVE]]
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: s_or_b64 exec, exec, [[SAVE]]
; GCN: buffer_store_dword
; GCN: s_endpgm
define void @min_long_forward_vbranch(i32 addrspace(1)* %arg) #0 {
bb:
%tid = call i32 @llvm.amdgcn.workitem.id.x()
%tid.ext = zext i32 %tid to i64
%gep = getelementptr inbounds i32, i32 addrspace(1)* %arg, i64 %tid.ext
%load = load volatile i32, i32 addrspace(1)* %gep
%cmp = icmp eq i32 %load, 0
br i1 %cmp, label %bb3, label %bb2 ; + 8 dword branch
bb2:
call void asm sideeffect " ; 32 bytes
v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %bb3
bb3:
store volatile i32 %load, i32 addrspace(1)* %gep
ret void
}
; FIXME: Should be able to use s_cbranch_scc0
; GCN-LABEL: {{^}}long_backward_sbranch:
; GCN: v_mov_b32_e32 [[LOOPIDX:v[0-9]+]], 0{{$}}
; GCN: [[LOOPBB:BB[0-9]+_[0-9]+]]: ; %bb2
; GCN-NEXT: ; =>This Inner Loop Header: Depth=1
; GCN-NEXT: v_add_i32_e32 [[INC:v[0-9]+]], vcc, 1, [[LOOPIDX]]
; GCN-NEXT: v_cmp_gt_i32_e32 vcc, 10, [[INC]]
; GCN-NEXT: ;;#ASMSTART
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: s_and_b64 vcc, exec, vcc
; GCN-NEXT: s_cbranch_vccz [[ENDBB:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONG_JUMP:BB[0-9]+_[0-9]+]]: ; %bb2
; GCN-NEXT: ; in Loop: Header=[[LOOPBB]] Depth=1
; GCN-NEXT: s_getpc_b64 vcc
; GCN-NEXT: s_sub_u32 vcc_lo, vcc_lo, ([[LONG_JUMP]]+4)-[[LOOPBB]]
; GCN-NEXT: s_subb_u32 vcc_hi, vcc_hi, 0
; GCN-NEXT: s_setpc_b64 vcc
; GCN-NEXT: [[ENDBB]]:
; GCN-NEXT: s_endpgm
define void @long_backward_sbranch(i32 addrspace(1)* %arg) #0 {
bb:
br label %bb2
bb2:
%loop.idx = phi i32 [ 0, %bb ], [ %inc, %bb2 ]
; 24 bytes
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
%inc = add nsw i32 %loop.idx, 1 ; add cost 4
%cmp = icmp slt i32 %inc, 10 ; condition cost = 8
br i1 %cmp, label %bb2, label %bb3 ; -
bb3:
ret void
}
; Requires expansion of unconditional branch from %bb2 to %bb4 (and
; expansion of conditional branch from %bb to %bb3.
; GCN-LABEL: {{^}}uniform_unconditional_min_long_forward_branch:
; GCN: s_cmp_eq_u32
; GCN-NEXT: s_cbranch_scc0 [[BB2:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONG_JUMP0:BB[0-9]+_[0-9]+]]: ; %bb0
; GCN-NEXT: s_getpc_b64 vcc
; GCN-NEXT: s_add_u32 vcc_lo, vcc_lo, [[BB3:BB[0-9]_[0-9]+]]-([[LONG_JUMP0]]+4)
; GCN-NEXT: s_addc_u32 vcc_hi, vcc_hi, 0{{$}}
; GCN-NEXT: s_setpc_b64 vcc
; GCN-NEXT: [[BB2]]: ; %bb2
; GCN: v_mov_b32_e32 [[BB2_K:v[0-9]+]], 17
; GCN: buffer_store_dword [[BB2_K]]
; GCN: s_waitcnt vmcnt(0)
; GCN-NEXT: [[LONG_JUMP1:BB[0-9]+_[0-9]+]]: ; %bb2
; GCN-NEXT: s_getpc_b64 vcc
; GCN-NEXT: s_add_u32 vcc_lo, vcc_lo, [[BB4:BB[0-9]_[0-9]+]]-([[LONG_JUMP1]]+4)
; GCN-NEXT: s_addc_u32 vcc_hi, vcc_hi, 0{{$}}
; GCN-NEXT: s_setpc_b64 vcc
; GCN: [[BB3]]: ; %bb3
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: ;;#ASMEND
; GCN-NEXT: [[BB4]]: ; %bb4
; GCN: v_mov_b32_e32 [[BB4_K:v[0-9]+]], 63
; GCN: buffer_store_dword [[BB4_K]]
; GCN-NEXT: s_endpgm
; GCN-NEXT: .Lfunc_end{{[0-9]+}}:
define void @uniform_unconditional_min_long_forward_branch(i32 addrspace(1)* %arg, i32 %arg1) {
bb0:
%tmp = icmp ne i32 %arg1, 0
br i1 %tmp, label %bb2, label %bb3
bb2:
store volatile i32 17, i32 addrspace(1)* undef
br label %bb4
bb3:
; 32 byte asm
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %bb4
bb4:
store volatile i32 63, i32 addrspace(1)* %arg
ret void
}
; GCN-LABEL: {{^}}uniform_unconditional_min_long_backward_branch:
; GCN-NEXT: ; BB#0: ; %entry
; GCN-NEXT: [[LOOP:BB[0-9]_[0-9]+]]: ; %loop
; GCN-NEXT: ; =>This Inner Loop Header: Depth=1
; GCN-NEXT: ;;#ASMSTART
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: [[LONGBB:BB[0-9]+_[0-9]+]]: ; %loop
; GCN-NEXT: ; in Loop: Header=[[LOOP]] Depth=1
; GCN-NEXT: s_getpc_b64 vcc
; GCN-NEXT: s_sub_u32 vcc_lo, vcc_lo, ([[LONGBB]]+4)-[[LOOP]]
; GCN-NEXT: s_subb_u32 vcc_hi, vcc_hi, 0{{$}}
; GCN-NEXT: s_setpc_b64 vcc
; GCN-NEXT .Lfunc_end{{[0-9]+}}:
define void @uniform_unconditional_min_long_backward_branch(i32 addrspace(1)* %arg, i32 %arg1) {
entry:
br label %loop
loop:
; 32 byte asm
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %loop
}
; Expansion of branch from %bb1 to %bb3 introduces need to expand
; branch from %bb0 to %bb2
; GCN-LABEL: {{^}}expand_requires_expand:
; GCN-NEXT: ; BB#0: ; %bb0
; GCN: s_load_dword
; GCN: s_cmp_lt_i32 s{{[0-9]+}}, 0{{$}}
; GCN-NEXT: s_cbranch_scc0 [[BB1:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONGBB0:BB[0-9]+_[0-9]+]]: ; %bb0
; GCN-NEXT: s_getpc_b64 vcc
; GCN-NEXT: s_add_u32 vcc_lo, vcc_lo, [[BB2:BB[0-9]_[0-9]+]]-([[LONGBB0]]+4)
; GCN-NEXT: s_addc_u32 vcc_hi, vcc_hi, 0{{$}}
; GCN-NEXT: s_setpc_b64 vcc
; GCN-NEXT: [[BB1]]: ; %bb1
; GCN-NEXT: s_load_dword
; GCN-NEXT: s_waitcnt lgkmcnt(0)
; GCN-NEXT: s_cmp_eq_u32 s{{[0-9]+}}, 3{{$}}
; GCN-NEXT: s_cbranch_scc0 [[BB2:BB[0-9]_[0-9]+]]
; GCN-NEXT: [[LONGBB1:BB[0-9]+_[0-9]+]]: ; %bb1
; GCN-NEXT: s_getpc_b64 vcc
; GCN-NEXT: s_add_u32 vcc_lo, vcc_lo, [[BB3:BB[0-9]+_[0-9]+]]-([[LONGBB1]]+4)
; GCN-NEXT: s_addc_u32 vcc_hi, vcc_hi, 0{{$}}
; GCN-NEXT: s_setpc_b64 vcc
; GCN-NEXT: [[BB2]]: ; %bb2
; GCN-NEXT: ;;#ASMSTART
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: [[BB3]]: ; %bb3
; GCN-NEXT: s_endpgm
define void @expand_requires_expand(i32 %cond0) #0 {
bb0:
%tmp = tail call i32 @llvm.amdgcn.workitem.id.x() #0
%cmp0 = icmp slt i32 %cond0, 0
br i1 %cmp0, label %bb2, label %bb1
bb1:
%val = load volatile i32, i32 addrspace(2)* undef
%cmp1 = icmp eq i32 %val, 3
br i1 %cmp1, label %bb3, label %bb2
bb2:
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %bb3
bb3:
ret void
}
; Requires expanding of required skip branch.
; GCN-LABEL: {{^}}uniform_inside_divergent:
; GCN: v_cmp_gt_u32_e32 vcc, 16, v{{[0-9]+}}
; GCN-NEXT: s_and_saveexec_b64 [[MASK:s\[[0-9]+:[0-9]+\]]], vcc
; GCN-NEXT: s_xor_b64 [[MASK1:s\[[0-9]+:[0-9]+\]]], exec, [[MASK]]
; GCN-NEXT: ; mask branch [[ENDIF:BB[0-9]+_[0-9]+]]
; GCN-NEXT: s_cbranch_execnz [[IF:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONGBB:BB[0-9]+_[0-9]+]]: ; %entry
; GCN-NEXT: s_getpc_b64 vcc
; GCN-NEXT: s_add_u32 vcc_lo, vcc_lo, [[BB2:BB[0-9]_[0-9]+]]-([[LONGBB]]+4)
; GCN-NEXT: s_addc_u32 vcc_hi, vcc_hi, 0{{$}}
; GCN-NEXT: s_setpc_b64 vcc
; GCN-NEXT: [[IF]]: ; %if
; GCN: buffer_store_dword
; GCN: s_cmp_lg_u32
; GCN: s_cbranch_scc1 [[ENDIF]]
; GCN-NEXT: ; BB#2: ; %if_uniform
; GCN: buffer_store_dword
; GCN: s_waitcnt vmcnt(0)
; GCN-NEXT: [[ENDIF]]: ; %endif
; GCN-NEXT: s_or_b64 exec, exec, [[MASK]]
; GCN-NEXT: s_endpgm
define void @uniform_inside_divergent(i32 addrspace(1)* %out, i32 %cond) #0 {
entry:
%tid = call i32 @llvm.amdgcn.workitem.id.x()
%d_cmp = icmp ult i32 %tid, 16
br i1 %d_cmp, label %if, label %endif
if:
store i32 0, i32 addrspace(1)* %out
%u_cmp = icmp eq i32 %cond, 0
br i1 %u_cmp, label %if_uniform, label %endif
if_uniform:
store i32 1, i32 addrspace(1)* %out
br label %endif
endif:
ret void
}
; si_mask_branch
; s_cbranch_execz
; s_branch
; GCN-LABEL: {{^}}analyze_mask_branch:
; GCN: v_cmp_lt_f32_e32 vcc
; GCN-NEXT: s_and_saveexec_b64 [[MASK:s\[[0-9]+:[0-9]+\]]], vcc
; GCN-NEXT: s_xor_b64 [[MASK]], exec, [[MASK]]
; GCN-NEXT: ; mask branch [[RET:BB[0-9]+_[0-9]+]]
; GCN-NEXT: s_cbranch_execz [[BRANCH_SKIP:BB[0-9]+_[0-9]+]]
; GCN-NEXT: s_branch [[LOOP_BODY:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[BRANCH_SKIP]]: ; %entry
; GCN-NEXT: s_getpc_b64 vcc
; GCN-NEXT: s_add_u32 vcc_lo, vcc_lo, [[RET]]-([[BRANCH_SKIP]]+4)
; GCN-NEXT: s_addc_u32 vcc_hi, vcc_hi, 0
; GCN-NEXT: s_setpc_b64 vcc
; GCN-NEXT: [[LOOP_BODY]]: ; %loop_body
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: ;;#ASMEND
; GCN-NEXT: s_and_b64 vcc, exec, -1{{$}}
; GCN-NEXT: s_cbranch_vccz [[RET]]
; GCN-NEXT: [[LONGBB:BB[0-9]+_[0-9]+]]: ; %loop_body
; GCN-NEXT: ; in Loop: Header=[[LOOP_BODY]] Depth=1
; GCN-NEXT: s_getpc_b64 vcc
; GCN-NEXT: s_sub_u32 vcc_lo, vcc_lo, ([[LONGBB]]+4)-[[LOOP_BODY]]
; GCN-NEXT: s_subb_u32 vcc_hi, vcc_hi, 0
; GCN-NEXT: s_setpc_b64 vcc
; GCN-NEXT: [[RET]]: ; %Flow
; GCN-NEXT: s_or_b64 exec, exec, [[MASK]]
; GCN: buffer_store_dword
; GCN-NEXT: s_endpgm
define void @analyze_mask_branch() #0 {
entry:
%reg = call float asm sideeffect "v_mov_b32_e64 $0, 0", "=v"()
%cmp0 = fcmp ogt float %reg, 0.000000e+00
br i1 %cmp0, label %loop, label %ret
loop:
%phi = phi float [ 0.000000e+00, %loop_body ], [ 1.000000e+00, %entry ]
call void asm sideeffect
"v_nop_e64
v_nop_e64", ""() #0
%cmp1 = fcmp olt float %phi, 8.0
br i1 %cmp1, label %loop_body, label %ret
loop_body:
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %loop
ret:
store volatile i32 7, i32 addrspace(1)* undef
ret void
}
attributes #0 = { nounwind }
attributes #1 = { nounwind readnone }