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llvm-mirror/test/CodeGen/AMDGPU/sgpr-control-flow.ll
Alexander Timofeev dd292a30dc [AMDGPU] Come back patch for the 'Assign register class for cross block values according to the divergence.'
Detailed description:

    After https://reviews.llvm.org/D59990 submit several issues were discovered.
    Changes in common code were preserved but AMDGPU specific part was reverted to keep the backend working correctly.

    Discovered issues were addressed in the following commits:

    https://reviews.llvm.org/D67662
    https://reviews.llvm.org/D67101
    https://reviews.llvm.org/D63953
    https://reviews.llvm.org/D63731

    This change brings back AMDGPU specific changes.

  Reviewed by: rampitec, arsenm

  Differential Revision: https://reviews.llvm.org/D68635

llvm-svn: 374767
2019-10-14 12:01:10 +00:00

148 lines
4.1 KiB
LLVM

; RUN: llc -march=amdgcn -mcpu=tahiti -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=SI %s
;
;
; Most SALU instructions ignore control flow, so we need to make sure
; they don't overwrite values from other blocks.
; If the branch decision is made based on a value in an SGPR then all
; threads will execute the same code paths, so we don't need to worry
; about instructions in different blocks overwriting each other.
; SI-LABEL: {{^}}sgpr_if_else_salu_br:
; SI: s_add
; SI: s_branch
; SI: s_sub
define amdgpu_kernel void @sgpr_if_else_salu_br(i32 addrspace(1)* %out, i32 %a, i32 %b, i32 %c, i32 %d, i32 %e) {
entry:
%0 = icmp eq i32 %a, 0
br i1 %0, label %if, label %else
if:
%1 = sub i32 %b, %c
br label %endif
else:
%2 = add i32 %d, %e
br label %endif
endif:
%3 = phi i32 [%1, %if], [%2, %else]
%4 = add i32 %3, %a
store i32 %4, i32 addrspace(1)* %out
ret void
}
; SI-LABEL: {{^}}sgpr_if_else_salu_br_opt:
; SI: s_cmp_lg_u32
; SI: s_cbranch_scc0 [[IF:BB[0-9]+_[0-9]+]]
; SI: ; %bb.1: ; %else
; SI: s_load_dword [[LOAD0:s[0-9]+]], s{{\[[0-9]+:[0-9]+\]}}, 0x2e
; SI: s_load_dword [[LOAD1:s[0-9]+]], s{{\[[0-9]+:[0-9]+\]}}, 0x37
; SI-NOT: add
; SI: s_branch [[ENDIF:BB[0-9]+_[0-9]+]]
; SI: [[IF]]: ; %if
; SI: s_load_dword [[LOAD0]], s{{\[[0-9]+:[0-9]+\]}}, 0x1c
; SI: s_load_dword [[LOAD1]], s{{\[[0-9]+:[0-9]+\]}}, 0x25
; SI-NOT: add
; SI: [[ENDIF]]: ; %endif
; SI: s_add_i32 s{{[0-9]+}}, [[LOAD0]], [[LOAD1]]
; SI: buffer_store_dword
; SI-NEXT: s_endpgm
define amdgpu_kernel void @sgpr_if_else_salu_br_opt(i32 addrspace(1)* %out, [8 x i32], i32 %a, [8 x i32], i32 %b, [8 x i32], i32 %c, [8 x i32], i32 %d, [8 x i32], i32 %e) {
entry:
%cmp0 = icmp eq i32 %a, 0
br i1 %cmp0, label %if, label %else
if:
%add0 = add i32 %b, %c
br label %endif
else:
%add1 = add i32 %d, %e
br label %endif
endif:
%phi = phi i32 [%add0, %if], [%add1, %else]
%add2 = add i32 %phi, %a
store i32 %add2, i32 addrspace(1)* %out
ret void
}
; The two S_ADD instructions should write to different registers, since
; different threads will take different control flow paths.
; SI-LABEL: {{^}}sgpr_if_else_valu_br:
; SI: s_add_i32 [[SGPR:s[0-9]+]]
; SI-NOT: s_add_i32 [[SGPR]]
define amdgpu_kernel void @sgpr_if_else_valu_br(i32 addrspace(1)* %out, float %a, i32 %b, i32 %c, i32 %d, i32 %e) {
entry:
%tid = call i32 @llvm.amdgcn.workitem.id.x() #0
%tid_f = uitofp i32 %tid to float
%tmp1 = fcmp ueq float %tid_f, 0.0
br i1 %tmp1, label %if, label %else
if:
%tmp2 = add i32 %b, %c
br label %endif
else:
%tmp3 = add i32 %d, %e
br label %endif
endif:
%tmp4 = phi i32 [%tmp2, %if], [%tmp3, %else]
store i32 %tmp4, i32 addrspace(1)* %out
ret void
}
; SI-LABEL: {{^}}sgpr_if_else_valu_cmp_phi_br:
; SI: ; %else
; SI: buffer_load_dword [[AVAL:v[0-9]+]]
; SI: v_cmp_gt_i32_e32 vcc, 0, [[AVAL]]
; SI: s_and_b64 [[PHI:s\[[0-9]+:[0-9]+\]]], vcc, exec
; SI: ; %if
; SI: buffer_load_dword [[AVAL:v[0-9]+]]
; SI-DAG: v_cmp_eq_u32_e32 [[CMP_ELSE:vcc]], 0, [[AVAL]]
; SI-DAG: s_andn2_b64 [[PHI]], [[PHI]], exec
; SI-DAG: s_and_b64 [[TMP:s\[[0-9]+:[0-9]+\]]], [[CMP_ELSE]], exec
; SI: s_or_b64 [[PHI]], [[PHI]], [[TMP]]
; SI: ; %endif
; SI: v_cndmask_b32_e64 [[RESULT:v[0-9]+]], 0, -1, [[PHI]]
; SI: buffer_store_dword [[RESULT]],
define amdgpu_kernel void @sgpr_if_else_valu_cmp_phi_br(i32 addrspace(1)* %out, i32 addrspace(1)* %a, i32 addrspace(1)* %b) {
entry:
%tid = call i32 @llvm.amdgcn.workitem.id.x() #0
%tmp1 = icmp eq i32 %tid, 0
br i1 %tmp1, label %if, label %else
if:
%gep.if = getelementptr i32, i32 addrspace(1)* %a, i32 %tid
%a.val = load i32, i32 addrspace(1)* %gep.if
%cmp.if = icmp eq i32 %a.val, 0
br label %endif
else:
%gep.else = getelementptr i32, i32 addrspace(1)* %b, i32 %tid
%b.val = load i32, i32 addrspace(1)* %gep.else
%cmp.else = icmp slt i32 %b.val, 0
br label %endif
endif:
%tmp4 = phi i1 [%cmp.if, %if], [%cmp.else, %else]
%ext = sext i1 %tmp4 to i32
store i32 %ext, i32 addrspace(1)* %out
ret void
}
declare i32 @llvm.amdgcn.workitem.id.x() #0
attributes #0 = { readnone }