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bolt/deps/llvm-18.1.8/llvm/test/CodeGen/AMDGPU/GlobalISel/divergence-divergent-i1-phis-no-lane-mask-merging.ll
Sam Vervaeck 174b6f4d4e
Embed LLVM 18.1.8
2025-02-14 19:21:04 +01:00

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; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 3
; RUN: llc -global-isel -amdgpu-global-isel-risky-select -mtriple=amdgcn-amd-amdpal -mcpu=gfx1010 < %s | FileCheck -check-prefix=GFX10 %s
; Divergent phis that don't require lowering using lane mask merging
; - divergent phi that has divergent incoming value (this makes it divergent)
; but is reachable through only one path - branch instruction that chooses
; path is uniform
; - divergent phi that is used only inside the loop and has incoming from
; previous iteration. After phi-elimination (rewrite lane mask in phi def with
; lane mask value from previous iteration), phi will hold lane mask valid for
; current iteration which is fine since it is not used outside of the loop.
; And one more that is tricky (is branch divergent or not ?)
; "amdgpu-flat-work-group-size"="1,1" aka single lane execution does not stop
; shader from activating multiple lanes by using some intrinsic (entering wwm
; and using dpp instructions)
; - there are cases with single lane execution where branch instructions are not
; lowered to si_if (or other intrinsic branches) - with intention to use
; uniform branch after instruction selection?
; PhiIncomingAnalysis does not recognize G_BRCOND as divergent branch and does
; not perform lane mask merging
define amdgpu_ps void @divergent_i1_phi_uniform_branch(ptr addrspace(1) %out, i32 %tid, i32 inreg %cond, ptr addrspace(1) %dummyaddr) {
; GFX10-LABEL: divergent_i1_phi_uniform_branch:
; GFX10: ; %bb.0: ; %A
; GFX10-NEXT: s_cmp_lg_u32 s0, 0
; GFX10-NEXT: s_cbranch_scc0 .LBB0_2
; GFX10-NEXT: ; %bb.1:
; GFX10-NEXT: v_cmp_le_u32_e64 s0, 6, v2
; GFX10-NEXT: s_branch .LBB0_3
; GFX10-NEXT: .LBB0_2: ; %dummy
; GFX10-NEXT: v_mov_b32_e32 v5, 0x7b
; GFX10-NEXT: v_cmp_gt_u32_e64 s0, 1, v2
; GFX10-NEXT: global_store_dword v[3:4], v5, off
; GFX10-NEXT: .LBB0_3: ; %exit
; GFX10-NEXT: v_cndmask_b32_e64 v2, 0, -1, s0
; GFX10-NEXT: v_add_nc_u32_e32 v2, 2, v2
; GFX10-NEXT: global_store_dword v[0:1], v2, off
; GFX10-NEXT: s_endpgm
A:
%val_A = icmp uge i32 %tid, 6
%cmp = icmp eq i32 %cond, 0
br i1 %cmp, label %dummy, label %exit
dummy:
store i32 123, ptr addrspace(1) %dummyaddr
br label %B
B:
%val_B = icmp ult i32 %tid, 1
br label %exit
exit:
%phi = phi i1 [ %val_A, %A ], [ %val_B, %B ]
%sel = select i1 %phi, i32 1, i32 2
store i32 %sel, ptr addrspace(1) %out
ret void
}
; Fix me - there is no need to merge lane masks here
define amdgpu_ps void @divergent_i1_phi_uniform_branch_simple(ptr addrspace(1) %out, i32 %tid, i32 inreg %cond) {
; GFX10-LABEL: divergent_i1_phi_uniform_branch_simple:
; GFX10: ; %bb.0: ; %A
; GFX10-NEXT: s_cmp_lg_u32 s0, 0
; GFX10-NEXT: s_cbranch_scc0 .LBB1_2
; GFX10-NEXT: ; %bb.1:
; GFX10-NEXT: v_cmp_le_u32_e64 s0, 6, v2
; GFX10-NEXT: s_branch .LBB1_3
; GFX10-NEXT: .LBB1_2: ; %B
; GFX10-NEXT: v_cmp_gt_u32_e64 s0, 1, v2
; GFX10-NEXT: .LBB1_3: ; %exit
; GFX10-NEXT: v_cndmask_b32_e64 v2, 0, -1, s0
; GFX10-NEXT: v_add_nc_u32_e32 v2, 2, v2
; GFX10-NEXT: global_store_dword v[0:1], v2, off
; GFX10-NEXT: s_endpgm
A:
%val_A = icmp uge i32 %tid, 6
%cmp = icmp eq i32 %cond, 0
br i1 %cmp, label %B, label %exit
B:
%val_B = icmp ult i32 %tid, 1
br label %exit
exit:
%phi = phi i1 [ %val_A, %A ], [ %val_B, %B ]
%sel = select i1 %phi, i32 1, i32 2
store i32 %sel, ptr addrspace(1) %out
ret void
}
; Divergent i1 phi that uses value from previous iteration.
; Used only inside the loop (variable name is bool_counter)
define void @divergent_i1_phi_used_inside_loop(float %val, ptr %addr) {
; GFX10-LABEL: divergent_i1_phi_used_inside_loop:
; GFX10: ; %bb.0: ; %entry
; GFX10-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; GFX10-NEXT: s_mov_b32 s4, 0
; GFX10-NEXT: v_mov_b32_e32 v3, 1
; GFX10-NEXT: v_mov_b32_e32 v4, s4
; GFX10-NEXT: .LBB2_1: ; %loop
; GFX10-NEXT: ; =>This Inner Loop Header: Depth=1
; GFX10-NEXT: v_cvt_f32_u32_e32 v5, v4
; GFX10-NEXT: v_xor_b32_e32 v3, 1, v3
; GFX10-NEXT: v_add_nc_u32_e32 v4, 1, v4
; GFX10-NEXT: v_cmp_gt_f32_e32 vcc_lo, v5, v0
; GFX10-NEXT: s_or_b32 s4, vcc_lo, s4
; GFX10-NEXT: s_andn2_b32 exec_lo, exec_lo, s4
; GFX10-NEXT: s_cbranch_execnz .LBB2_1
; GFX10-NEXT: ; %bb.2: ; %exit
; GFX10-NEXT: s_or_b32 exec_lo, exec_lo, s4
; GFX10-NEXT: v_and_b32_e32 v0, 1, v3
; GFX10-NEXT: v_cmp_ne_u32_e32 vcc_lo, 0, v0
; GFX10-NEXT: v_cndmask_b32_e64 v0, 0, 1.0, vcc_lo
; GFX10-NEXT: flat_store_dword v[1:2], v0
; GFX10-NEXT: s_waitcnt lgkmcnt(0)
; GFX10-NEXT: s_setpc_b64 s[30:31]
entry:
br label %loop
loop:
%counter = phi i32 [ 0, %entry ], [ %counterPlus1, %loop ]
%bool_counter = phi i1 [ true, %entry ], [ %neg_bool_counter, %loop ]
%neg_bool_counter = xor i1 %bool_counter, true
%fcounter = uitofp i32 %counter to float
%cond = fcmp ogt float %fcounter, %val
%counterPlus1 = add i32 %counter, 1
br i1 %cond, label %exit, label %loop
exit:
%select = select i1 %neg_bool_counter, float 1.000000e+00, float 0.000000e+00
store float %select, ptr %addr
ret void
}
define void @divergent_i1_phi_used_inside_loop_bigger_loop_body(float %val, float %pre_cond_val, ptr %addr, ptr %addr_if, ptr %addr_else) {
; GFX10-LABEL: divergent_i1_phi_used_inside_loop_bigger_loop_body:
; GFX10: ; %bb.0: ; %entry
; GFX10-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; GFX10-NEXT: v_cmp_lt_f32_e32 vcc_lo, 1.0, v1
; GFX10-NEXT: s_mov_b32 s4, 0
; GFX10-NEXT: v_mov_b32_e32 v8, 0x3e8
; GFX10-NEXT: v_mov_b32_e32 v9, s4
; GFX10-NEXT: v_cndmask_b32_e64 v1, 0, 1, vcc_lo
; GFX10-NEXT: s_branch .LBB3_2
; GFX10-NEXT: .LBB3_1: ; %loop_body
; GFX10-NEXT: ; in Loop: Header=BB3_2 Depth=1
; GFX10-NEXT: v_cvt_f32_u32_e32 v10, v9
; GFX10-NEXT: v_xor_b32_e32 v1, 1, v1
; GFX10-NEXT: v_add_nc_u32_e32 v9, 1, v9
; GFX10-NEXT: v_cmp_gt_f32_e32 vcc_lo, v10, v0
; GFX10-NEXT: s_or_b32 s4, vcc_lo, s4
; GFX10-NEXT: s_andn2_b32 exec_lo, exec_lo, s4
; GFX10-NEXT: s_cbranch_execz .LBB3_6
; GFX10-NEXT: .LBB3_2: ; %loop_start
; GFX10-NEXT: ; =>This Inner Loop Header: Depth=1
; GFX10-NEXT: v_cmp_ge_i32_e32 vcc_lo, 0x3e8, v9
; GFX10-NEXT: s_mov_b32 s5, 1
; GFX10-NEXT: s_cbranch_vccz .LBB3_4
; GFX10-NEXT: ; %bb.3: ; %else
; GFX10-NEXT: ; in Loop: Header=BB3_2 Depth=1
; GFX10-NEXT: s_mov_b32 s5, 0
; GFX10-NEXT: flat_store_dword v[6:7], v8
; GFX10-NEXT: .LBB3_4: ; %Flow
; GFX10-NEXT: ; in Loop: Header=BB3_2 Depth=1
; GFX10-NEXT: s_xor_b32 s5, s5, 1
; GFX10-NEXT: s_and_b32 s5, s5, 1
; GFX10-NEXT: s_cmp_lg_u32 s5, 0
; GFX10-NEXT: s_cbranch_scc1 .LBB3_1
; GFX10-NEXT: ; %bb.5: ; %if
; GFX10-NEXT: ; in Loop: Header=BB3_2 Depth=1
; GFX10-NEXT: flat_store_dword v[4:5], v8
; GFX10-NEXT: s_branch .LBB3_1
; GFX10-NEXT: .LBB3_6: ; %exit
; GFX10-NEXT: s_or_b32 exec_lo, exec_lo, s4
; GFX10-NEXT: v_and_b32_e32 v0, 1, v1
; GFX10-NEXT: v_cmp_ne_u32_e32 vcc_lo, 0, v0
; GFX10-NEXT: v_cndmask_b32_e64 v0, 0, 1.0, vcc_lo
; GFX10-NEXT: flat_store_dword v[2:3], v0
; GFX10-NEXT: s_waitcnt lgkmcnt(0)
; GFX10-NEXT: s_setpc_b64 s[30:31]
entry:
%pre_cond = fcmp ogt float %pre_cond_val, 1.0
br label %loop_start
loop_start:
%counter = phi i32 [ 0, %entry ], [ %counterPlus1, %loop_body ]
%bool_counter = phi i1 [ %pre_cond, %entry ], [ %neg_bool_counter, %loop_body ]
%cond_break = icmp sgt i32 %counter, 1000
br i1 %cond_break, label %if, label %else
if:
store i32 1000, ptr %addr_if
br label %loop_body
else:
store i32 1000, ptr %addr_else
br label %loop_body
loop_body:
%neg_bool_counter = xor i1 %bool_counter, true
%fcounter = uitofp i32 %counter to float
%cond = fcmp ogt float %fcounter, %val
%counterPlus1 = add i32 %counter, 1
br i1 %cond, label %exit, label %loop_start
exit:
%select = select i1 %neg_bool_counter, float 1.000000e+00, float 0.000000e+00
store float %select, ptr %addr
ret void
}
; There is a divergent, according to machine uniformity info, g_brcond branch
; here, not lowered to si_if because of "amdgpu-flat-work-group-size"="1,1".
define amdgpu_cs void @single_lane_execution_attribute(i32 inreg %.userdata0, <3 x i32> inreg %.WorkgroupId, <3 x i32> %.LocalInvocationId) #0 {
; GFX10-LABEL: single_lane_execution_attribute:
; GFX10: ; %bb.0: ; %.entry
; GFX10-NEXT: s_mov_b32 s12, 0
; GFX10-NEXT: s_getpc_b64 s[4:5]
; GFX10-NEXT: s_mov_b32 s13, -1
; GFX10-NEXT: s_mov_b32 s2, s0
; GFX10-NEXT: s_and_b64 s[4:5], s[4:5], s[12:13]
; GFX10-NEXT: s_mov_b32 s3, s12
; GFX10-NEXT: v_mbcnt_lo_u32_b32 v1, -1, 0
; GFX10-NEXT: s_or_b64 s[2:3], s[4:5], s[2:3]
; GFX10-NEXT: s_load_dwordx8 s[4:11], s[2:3], 0x0
; GFX10-NEXT: s_mov_b32 s2, 1
; GFX10-NEXT: v_mbcnt_hi_u32_b32 v1, -1, v1
; GFX10-NEXT: v_lshlrev_b32_e32 v2, 2, v1
; GFX10-NEXT: v_and_b32_e32 v3, 1, v1
; GFX10-NEXT: v_xor_b32_e32 v3, 1, v3
; GFX10-NEXT: v_and_b32_e32 v3, 1, v3
; GFX10-NEXT: s_waitcnt lgkmcnt(0)
; GFX10-NEXT: buffer_load_dword v2, v2, s[4:7], 0 offen
; GFX10-NEXT: v_cmp_ne_u32_e32 vcc_lo, 0, v3
; GFX10-NEXT: ; implicit-def: $vgpr3
; GFX10-NEXT: s_waitcnt vmcnt(0)
; GFX10-NEXT: v_cmp_eq_u32_e64 s0, 0, v2
; GFX10-NEXT: s_cbranch_vccnz .LBB4_4
; GFX10-NEXT: ; %bb.1: ; %.preheader.preheader
; GFX10-NEXT: v_mov_b32_e32 v3, s12
; GFX10-NEXT: v_mov_b32_e32 v4, s12
; GFX10-NEXT: .LBB4_2: ; %.preheader
; GFX10-NEXT: ; =>This Inner Loop Header: Depth=1
; GFX10-NEXT: buffer_load_dword v5, v3, s[4:7], 0 offen
; GFX10-NEXT: v_add_nc_u32_e32 v1, -1, v1
; GFX10-NEXT: v_add_nc_u32_e32 v3, 4, v3
; GFX10-NEXT: v_cmp_ne_u32_e32 vcc_lo, 0, v1
; GFX10-NEXT: s_waitcnt vmcnt(0)
; GFX10-NEXT: v_add_nc_u32_e32 v4, v5, v4
; GFX10-NEXT: s_cbranch_vccnz .LBB4_2
; GFX10-NEXT: ; %bb.3: ; %.preheader._crit_edge
; GFX10-NEXT: v_cmp_eq_u32_e32 vcc_lo, v4, v2
; GFX10-NEXT: s_or_b32 s2, s0, vcc_lo
; GFX10-NEXT: v_cndmask_b32_e64 v3, 0, 1, s2
; GFX10-NEXT: s_mov_b32 s2, 0
; GFX10-NEXT: .LBB4_4: ; %Flow
; GFX10-NEXT: s_and_b32 s2, s2, 1
; GFX10-NEXT: s_cmp_lg_u32 s2, 0
; GFX10-NEXT: s_cbranch_scc0 .LBB4_6
; GFX10-NEXT: ; %bb.5: ; %.19
; GFX10-NEXT: v_cndmask_b32_e64 v1, 0, 1, s0
; GFX10-NEXT: v_or_b32_e32 v3, 2, v1
; GFX10-NEXT: .LBB4_6: ; %.22
; GFX10-NEXT: v_add_lshl_u32 v0, v0, s1, 2
; GFX10-NEXT: buffer_store_dword v3, v0, s[8:11], 0 offen
; GFX10-NEXT: s_endpgm
.entry:
%.0 = call i64 @llvm.amdgcn.s.getpc()
%.1 = and i64 %.0, -4294967296
%.2 = zext i32 %.userdata0 to i64
%.3 = or i64 %.1, %.2
%.4 = inttoptr i64 %.3 to ptr addrspace(4)
%.5 = getelementptr i8, ptr addrspace(4) %.4, i64 16
%.6 = load <4 x i32>, ptr addrspace(4) %.5, align 16
%.7 = load <4 x i32>, ptr addrspace(4) %.4, align 16
%.8 = call i32 @llvm.amdgcn.mbcnt.lo(i32 -1, i32 0)
%.9 = call i32 @llvm.amdgcn.mbcnt.hi(i32 -1, i32 %.8)
%.fr11 = freeze i32 %.9
%.idx = shl i32 %.fr11, 2
%.10 = call i32 @llvm.amdgcn.raw.buffer.load.i32(<4 x i32> %.7, i32 %.idx, i32 0, i32 0)
%.11 = icmp eq i32 %.10, 0
%.12 = and i32 %.fr11, 1
%.not = icmp eq i32 %.12, 0
br i1 %.not, label %.19, label %.preheader
.preheader: ; preds = %.entry, %.preheader
%._96.02 = phi i32 [ %.15, %.preheader ], [ 0, %.entry ]
%._50.01 = phi i32 [ %.14, %.preheader ], [ 0, %.entry ]
%.idx5 = shl i32 %._96.02, 2
%.13 = call i32 @llvm.amdgcn.raw.buffer.load.i32(<4 x i32> %.7, i32 %.idx5, i32 0, i32 0)
%.14 = add i32 %.13, %._50.01
%.15 = add nuw i32 %._96.02, 1
%.exitcond.not = icmp eq i32 %.15, %.fr11
br i1 %.exitcond.not, label %.preheader._crit_edge, label %.preheader
.preheader._crit_edge: ; preds = %.preheader
%.16 = icmp eq i32 %.14, %.10
%.17 = or i1 %.11, %.16
%.18 = zext i1 %.17 to i32
br label %.22
.19: ; preds = %.entry
%.20 = zext i1 %.11 to i32
%.21 = or i32 %.20, 2
br label %.22
.22: ; preds = %.19, %.preheader._crit_edge
%._51.0 = phi i32 [ %.18, %.preheader._crit_edge ], [ %.21, %.19 ]
%.WorkgroupId.i0 = extractelement <3 x i32> %.WorkgroupId, i64 0
%.LocalInvocationId.i0 = extractelement <3 x i32> %.LocalInvocationId, i64 0
%.i0 = add i32 %.LocalInvocationId.i0, %.WorkgroupId.i0
%.idx6 = shl i32 %.i0, 2
call void @llvm.amdgcn.raw.buffer.store.i32(i32 %._51.0, <4 x i32> %.6, i32 %.idx6, i32 0, i32 0)
ret void
}
; Function Attrs: nocallback nofree nosync nounwind willreturn memory(none)
declare i32 @llvm.amdgcn.mbcnt.lo(i32, i32)
; Function Attrs: nocallback nofree nosync nounwind willreturn memory(none)
declare i32 @llvm.amdgcn.mbcnt.hi(i32, i32)
; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare i64 @llvm.amdgcn.s.getpc()
; Function Attrs: nocallback nofree nosync nounwind willreturn memory(read)
declare i32 @llvm.amdgcn.raw.buffer.load.i32(<4 x i32>, i32, i32, i32 immarg)
; Function Attrs: nocallback nofree nosync nounwind willreturn memory(write)
declare void @llvm.amdgcn.raw.buffer.store.i32(i32, <4 x i32>, i32, i32, i32 immarg)
attributes #0 = { nounwind memory(readwrite) "amdgpu-flat-work-group-size"="1,1" }
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