llvm-project/llvm/test/CodeGen/AMDGPU/wqm.ll

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; RUN: llc -march=amdgcn -mcpu=verde -verify-machineinstrs < %s | FileCheck -check-prefix=CHECK -check-prefix=SI %s
; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs < %s | FileCheck -check-prefix=CHECK -check-prefix=VI %s
; Check that WQM isn't triggered by image load/store intrinsics.
;
;CHECK-LABEL: {{^}}test1:
;CHECK-NOT: s_wqm
define amdgpu_ps <4 x float> @test1(<8 x i32> inreg %rsrc, <4 x i32> %c) {
main_body:
%tex = call <4 x float> @llvm.amdgcn.image.load.v4f32.v4i32.v8i32(<4 x i32> %c, <8 x i32> %rsrc, i32 15, i1 0, i1 0, i1 0, i1 0)
call void @llvm.amdgcn.image.store.v4f32.v4i32.v8i32(<4 x float> %tex, <4 x i32> %c, <8 x i32> %rsrc, i32 15, i1 0, i1 0, i1 0, i1 0)
ret <4 x float> %tex
}
; Check that WQM is triggered by code calculating inputs to image samples and is disabled as soon as possible
;
;CHECK-LABEL: {{^}}test2:
;CHECK-NEXT: ; %main_body
;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
;CHECK-NEXT: s_wqm_b64 exec, exec
;CHECK: interp
;CHECK: s_and_b64 exec, exec, [[ORIG]]
;CHECK-NOT: interp
;CHECK: image_sample
;CHECK-NOT: exec
;CHECK: .size test2
define amdgpu_ps <4 x float> @test2(i32 inreg, i32 inreg, i32 inreg, i32 inreg %m0, <8 x i32> inreg %rsrc, <4 x i32> inreg %sampler, <2 x float> %pos) #6 {
main_body:
%inst23 = extractelement <2 x float> %pos, i32 0
%inst24 = extractelement <2 x float> %pos, i32 1
%inst25 = tail call float @llvm.amdgcn.interp.p1(float %inst23, i32 0, i32 0, i32 %m0)
%inst26 = tail call float @llvm.amdgcn.interp.p2(float %inst25, float %inst24, i32 0, i32 0, i32 %m0)
%inst27 = insertelement <2 x float> undef, float %inst26, i32 0
%inst28 = tail call float @llvm.amdgcn.interp.p1(float %inst23, i32 1, i32 0, i32 %m0)
%inst29 = tail call float @llvm.amdgcn.interp.p2(float %inst28, float %inst24, i32 1, i32 0, i32 %m0)
%inst30 = insertelement <2 x float> %inst27, float %inst29, i32 1
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v2f32.v8i32(<2 x float> %inst30, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
ret <4 x float> %tex
}
; ... but disabled for stores (and, in this simple case, not re-enabled) ...
;
;CHECK-LABEL: {{^}}test3:
;CHECK-NEXT: ; %main_body
;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
;CHECK-NEXT: s_wqm_b64 exec, exec
;CHECK: s_and_b64 exec, exec, [[ORIG]]
;CHECK: image_sample
;CHECK: store
;CHECK-NOT: exec
;CHECK: .size test3
define amdgpu_ps <4 x float> @test3(<8 x i32> inreg %rsrc, <4 x i32> inreg %sampler, <4 x float> %c) {
main_body:
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> %c, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%tex.1 = bitcast <4 x float> %tex to <4 x i32>
%tex.2 = extractelement <4 x i32> %tex.1, i32 0
call void @llvm.amdgcn.buffer.store.v4f32(<4 x float> %tex, <4 x i32> undef, i32 %tex.2, i32 0, i1 0, i1 0)
ret <4 x float> %tex
}
; ... and disabled for export.
;
;CHECK-LABEL: {{^}}test3x:
;CHECK-NEXT: ; %main_body
;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
;CHECK-NEXT: s_wqm_b64 exec, exec
;CHECK: s_and_b64 exec, exec, [[ORIG]]
;CHECK: image_sample
;CHECK: exp
;CHECK-NOT: exec
;CHECK: .size test3x
define amdgpu_ps void @test3x(i32 inreg, i32 inreg, i32 inreg, i32 inreg %m0, <8 x i32> inreg %rsrc, <4 x i32> inreg %sampler, <2 x float> %pos) #6 {
main_body:
%inst23 = extractelement <2 x float> %pos, i32 0
%inst24 = extractelement <2 x float> %pos, i32 1
%inst25 = tail call float @llvm.amdgcn.interp.p1(float %inst23, i32 0, i32 0, i32 %m0)
%inst26 = tail call float @llvm.amdgcn.interp.p2(float %inst25, float %inst24, i32 0, i32 0, i32 %m0)
%inst27 = insertelement <2 x float> undef, float %inst26, i32 0
%inst28 = tail call float @llvm.amdgcn.interp.p1(float %inst23, i32 1, i32 0, i32 %m0)
%inst29 = tail call float @llvm.amdgcn.interp.p2(float %inst28, float %inst24, i32 1, i32 0, i32 %m0)
%inst30 = insertelement <2 x float> %inst27, float %inst29, i32 1
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v2f32.v8i32(<2 x float> %inst30, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%tex.0 = extractelement <4 x float> %tex, i32 0
%tex.1 = extractelement <4 x float> %tex, i32 1
%tex.2 = extractelement <4 x float> %tex, i32 2
%tex.3 = extractelement <4 x float> %tex, i32 3
call void @llvm.amdgcn.exp.f32(i32 0, i32 15, float %tex.0, float %tex.1, float %tex.2, float %tex.3, i1 true, i1 true)
ret void
}
; Check that WQM is re-enabled when required.
;
;CHECK-LABEL: {{^}}test4:
;CHECK-NEXT: ; %main_body
;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
;CHECK-NEXT: s_wqm_b64 exec, exec
;CHECK: v_mul_lo_i32 [[MUL:v[0-9]+]], v0, v1
;CHECK: s_and_b64 exec, exec, [[ORIG]]
;CHECK: store
;CHECK: s_wqm_b64 exec, exec
;CHECK: image_sample
;CHECK: image_sample
define amdgpu_ps <4 x float> @test4(<8 x i32> inreg %rsrc, <4 x i32> inreg %sampler, float addrspace(1)* inreg %ptr, i32 %c, i32 %d, float %data) {
main_body:
%c.1 = mul i32 %c, %d
call void @llvm.amdgcn.buffer.store.v4f32(<4 x float> undef, <4 x i32> undef, i32 %c.1, i32 0, i1 0, i1 0)
%c.1.bc = bitcast i32 %c.1 to float
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float %c.1.bc, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%dtex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> %tex, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
ret <4 x float> %dtex
}
; Check that WQM is triggered by the wqm intrinsic.
;
;CHECK-LABEL: {{^}}test5:
;CHECK: s_wqm_b64 exec, exec
;CHECK: buffer_load_dword
;CHECK: buffer_load_dword
;CHECK: v_add_f32_e32
define amdgpu_ps float @test5(i32 inreg %idx0, i32 inreg %idx1) {
main_body:
%src0 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx0, i32 0, i1 0, i1 0)
%src1 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx1, i32 0, i1 0, i1 0)
%out = fadd float %src0, %src1
%out.0 = call float @llvm.amdgcn.wqm.f32(float %out)
ret float %out.0
}
; Check that the wqm intrinsic works correctly for integers.
;
;CHECK-LABEL: {{^}}test6:
;CHECK: s_wqm_b64 exec, exec
;CHECK: buffer_load_dword
;CHECK: buffer_load_dword
;CHECK: v_add_f32_e32
define amdgpu_ps float @test6(i32 inreg %idx0, i32 inreg %idx1) {
main_body:
%src0 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx0, i32 0, i1 0, i1 0)
%src1 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx1, i32 0, i1 0, i1 0)
%out = fadd float %src0, %src1
%out.0 = bitcast float %out to i32
%out.1 = call i32 @llvm.amdgcn.wqm.i32(i32 %out.0)
%out.2 = bitcast i32 %out.1 to float
ret float %out.2
}
[AMDGPU] Add support for Whole Wavefront Mode Summary: Whole Wavefront Wode (WWM) is similar to WQM, except that all of the lanes are always enabled, regardless of control flow. This is required for implementing wavefront reductions in non-uniform control flow, where we need to use the inactive lanes to propagate intermediate results, so they need to be enabled. We need to propagate WWM to uses (unless they're explicitly marked as exact) so that they also propagate intermediate results correctly. We do the analysis and exec mask munging during the WQM pass, since there are interactions with WQM for things that require both WQM and WWM. For simplicity, WWM is entirely block-local -- blocks are never WWM on entry or exit of a block, and WWM is not propagated to the block level. This means that computations involving WWM cannot involve control flow, but we only ever plan to use WWM for a few limited purposes (none of which involve control flow) anyways. Shaders can ask for WWM using the @llvm.amdgcn.wwm intrinsic. There isn't yet a way to turn WWM off -- that will be added in a future change. Finally, it turns out that turning on inactive lanes causes a number of problems with register allocation. While the best long-term solution seems like teaching LLVM's register allocator about predication, for now we need to add some hacks to prevent ourselves from getting into trouble due to constraints that aren't currently expressed in LLVM. For the gory details, see the comments at the top of SIFixWWMLiveness.cpp. Reviewers: arsenm, nhaehnle, tpr Subscribers: kzhuravl, wdng, mgorny, yaxunl, dstuttard, t-tye, llvm-commits Differential Revision: https://reviews.llvm.org/D35524 llvm-svn: 310087
2017-08-05 02:36:52 +08:00
; Check that WWM is triggered by the wwm intrinsic.
;
;CHECK-LABEL: {{^}}test_wwm1:
;CHECK: s_or_saveexec_b64 s{{\[[0-9]+:[0-9]+\]}}, -1
;CHECK: buffer_load_dword
;CHECK: buffer_load_dword
;CHECK: v_add_f32_e32
define amdgpu_ps float @test_wwm1(i32 inreg %idx0, i32 inreg %idx1) {
main_body:
%src0 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx0, i32 0, i1 0, i1 0)
%src1 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx1, i32 0, i1 0, i1 0)
%out = fadd float %src0, %src1
%out.0 = call float @llvm.amdgcn.wwm.f32(float %out)
ret float %out.0
}
; Same as above, but with an integer type.
;
;CHECK-LABEL: {{^}}test_wwm2:
;CHECK: s_or_saveexec_b64 s{{\[[0-9]+:[0-9]+\]}}, -1
;CHECK: buffer_load_dword
;CHECK: buffer_load_dword
;CHECK: v_add_{{[iu]}}32_e32
[AMDGPU] Add support for Whole Wavefront Mode Summary: Whole Wavefront Wode (WWM) is similar to WQM, except that all of the lanes are always enabled, regardless of control flow. This is required for implementing wavefront reductions in non-uniform control flow, where we need to use the inactive lanes to propagate intermediate results, so they need to be enabled. We need to propagate WWM to uses (unless they're explicitly marked as exact) so that they also propagate intermediate results correctly. We do the analysis and exec mask munging during the WQM pass, since there are interactions with WQM for things that require both WQM and WWM. For simplicity, WWM is entirely block-local -- blocks are never WWM on entry or exit of a block, and WWM is not propagated to the block level. This means that computations involving WWM cannot involve control flow, but we only ever plan to use WWM for a few limited purposes (none of which involve control flow) anyways. Shaders can ask for WWM using the @llvm.amdgcn.wwm intrinsic. There isn't yet a way to turn WWM off -- that will be added in a future change. Finally, it turns out that turning on inactive lanes causes a number of problems with register allocation. While the best long-term solution seems like teaching LLVM's register allocator about predication, for now we need to add some hacks to prevent ourselves from getting into trouble due to constraints that aren't currently expressed in LLVM. For the gory details, see the comments at the top of SIFixWWMLiveness.cpp. Reviewers: arsenm, nhaehnle, tpr Subscribers: kzhuravl, wdng, mgorny, yaxunl, dstuttard, t-tye, llvm-commits Differential Revision: https://reviews.llvm.org/D35524 llvm-svn: 310087
2017-08-05 02:36:52 +08:00
define amdgpu_ps float @test_wwm2(i32 inreg %idx0, i32 inreg %idx1) {
main_body:
%src0 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx0, i32 0, i1 0, i1 0)
%src1 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx1, i32 0, i1 0, i1 0)
%src0.0 = bitcast float %src0 to i32
%src1.0 = bitcast float %src1 to i32
%out = add i32 %src0.0, %src1.0
%out.0 = call i32 @llvm.amdgcn.wwm.i32(i32 %out)
%out.1 = bitcast i32 %out.0 to float
ret float %out.1
}
; Check that we don't leave WWM on for computations that don't require WWM,
; since that will lead clobbering things that aren't supposed to be clobbered
; in cases like this.
;
;CHECK-LABEL: {{^}}test_wwm3:
;CHECK: s_or_saveexec_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], -1
;CHECK: buffer_load_dword
;CHECK: v_add_f32_e32
;CHECK: s_mov_b64 exec, [[ORIG]]
;CHECK: v_add_f32_e32
define amdgpu_ps float @test_wwm3(i32 inreg %idx) {
main_body:
; use mbcnt to make sure the branch is divergent
%lo = call i32 @llvm.amdgcn.mbcnt.lo(i32 -1, i32 0)
%hi = call i32 @llvm.amdgcn.mbcnt.hi(i32 -1, i32 %lo)
%cc = icmp uge i32 %hi, 32
br i1 %cc, label %endif, label %if
if:
%src = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx, i32 0, i1 0, i1 0)
%out = fadd float %src, %src
%out.0 = call float @llvm.amdgcn.wwm.f32(float %out)
%out.1 = fadd float %src, %out.0
br label %endif
endif:
%out.2 = phi float [ %out.1, %if ], [ 0.0, %main_body ]
ret float %out.2
}
; Check that WWM writes aren't coalesced with non-WWM writes, since the WWM
; write could clobber disabled channels in the non-WWM one.
;
;CHECK-LABEL: {{^}}test_wwm4:
;CHECK: s_or_saveexec_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], -1
;CHECK: buffer_load_dword
;CHECK: v_add_f32_e32
;CHECK: s_mov_b64 exec, [[ORIG]]
;CHECK-NEXT: v_mov_b32_e32
define amdgpu_ps float @test_wwm4(i32 inreg %idx) {
main_body:
; use mbcnt to make sure the branch is divergent
%lo = call i32 @llvm.amdgcn.mbcnt.lo(i32 -1, i32 0)
%hi = call i32 @llvm.amdgcn.mbcnt.hi(i32 -1, i32 %lo)
%cc = icmp uge i32 %hi, 32
br i1 %cc, label %endif, label %if
if:
%src = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx, i32 0, i1 0, i1 0)
%out = fadd float %src, %src
%out.0 = call float @llvm.amdgcn.wwm.f32(float %out)
br label %endif
endif:
%out.1 = phi float [ %out.0, %if ], [ 0.0, %main_body ]
ret float %out.1
}
; Make sure the transition from Exact to WWM then WQM works properly.
;
;CHECK-LABEL: {{^}}test_wwm5:
;CHECK: buffer_load_dword
;CHECK: buffer_store_dword
;CHECK: s_or_saveexec_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], -1
;CHECK: buffer_load_dword
;CHECK: v_add_f32_e32
;CHECK: s_mov_b64 exec, [[ORIG]]
;CHECK: s_wqm_b64 exec, exec
define amdgpu_ps float @test_wwm5(i32 inreg %idx0, i32 inreg %idx1) {
main_body:
%src0 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx0, i32 0, i1 0, i1 0)
call void @llvm.amdgcn.buffer.store.f32(float %src0, <4 x i32> undef, i32 %idx0, i32 0, i1 0, i1 0)
%src1 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx1, i32 0, i1 0, i1 0)
%temp = fadd float %src1, %src1
%temp.0 = call float @llvm.amdgcn.wwm.f32(float %temp)
%out = fadd float %temp.0, %temp.0
%out.0 = call float @llvm.amdgcn.wqm.f32(float %out)
ret float %out.0
}
; Check that WWM is turned on correctly across basic block boundaries.
;
;CHECK-LABEL: {{^}}test_wwm6:
;CHECK: s_or_saveexec_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], -1
;SI-CHECK: buffer_load_dword
;VI-CHECK: flat_load_dword
;CHECK: s_mov_b64 exec, [[ORIG]]
;CHECK: %if
;CHECK: s_or_saveexec_b64 [[ORIG2:s\[[0-9]+:[0-9]+\]]], -1
;SI-CHECK: buffer_load_dword
;VI-CHECK: flat_load_dword
;CHECK: v_add_f32_e32
;CHECK: s_mov_b64 exec, [[ORIG2]]
define amdgpu_ps float @test_wwm6() {
main_body:
%src0 = load volatile float, float addrspace(1)* undef
; use mbcnt to make sure the branch is divergent
%lo = call i32 @llvm.amdgcn.mbcnt.lo(i32 -1, i32 0)
%hi = call i32 @llvm.amdgcn.mbcnt.hi(i32 -1, i32 %lo)
%cc = icmp uge i32 %hi, 32
br i1 %cc, label %endif, label %if
if:
%src1 = load volatile float, float addrspace(1)* undef
%out = fadd float %src0, %src1
%out.0 = call float @llvm.amdgcn.wwm.f32(float %out)
br label %endif
endif:
%out.1 = phi float [ %out.0, %if ], [ 0.0, %main_body ]
ret float %out.1
}
; Check that @llvm.amdgcn.set.inactive disables WWM.
;
;CHECK-LABEL: {{^}}test_set_inactive1:
;CHECK: buffer_load_dword
;CHECK: s_not_b64 exec, exec
;CHECK: v_mov_b32_e32
;CHECK: s_not_b64 exec, exec
;CHECK: s_or_saveexec_b64 s{{\[[0-9]+:[0-9]+\]}}, -1
;CHECK: v_add_{{[iu]}}32_e32
define amdgpu_ps void @test_set_inactive1(i32 inreg %idx) {
main_body:
%src = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx, i32 0, i1 0, i1 0)
%src.0 = bitcast float %src to i32
%src.1 = call i32 @llvm.amdgcn.set.inactive.i32(i32 %src.0, i32 0)
%out = add i32 %src.1, %src.1
%out.0 = call i32 @llvm.amdgcn.wwm.i32(i32 %out)
%out.1 = bitcast i32 %out.0 to float
call void @llvm.amdgcn.buffer.store.f32(float %out.1, <4 x i32> undef, i32 %idx, i32 0, i1 0, i1 0)
ret void
}
; Check that enabling WQM anywhere enables WQM for the set.inactive source.
;
;CHECK-LABEL: {{^}}test_set_inactive2:
;CHECK: s_wqm_b64 exec, exec
;CHECK: buffer_load_dword
;CHECK: buffer_load_dword
define amdgpu_ps void @test_set_inactive2(i32 inreg %idx0, i32 inreg %idx1) {
main_body:
%src1 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx1, i32 0, i1 0, i1 0)
%src1.0 = bitcast float %src1 to i32
%src1.1 = call i32 @llvm.amdgcn.set.inactive.i32(i32 %src1.0, i32 undef)
%src0 = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx0, i32 0, i1 0, i1 0)
%src0.0 = bitcast float %src0 to i32
%src0.1 = call i32 @llvm.amdgcn.wqm.i32(i32 %src0.0)
%out = add i32 %src0.1, %src1.1
%out.0 = bitcast i32 %out to float
call void @llvm.amdgcn.buffer.store.f32(float %out.0, <4 x i32> undef, i32 %idx1, i32 0, i1 0, i1 0)
ret void
}
; Check a case of one branch of an if-else requiring WQM, the other requiring
; exact.
;
; Note: In this particular case, the save-and-restore could be avoided if the
; analysis understood that the two branches of the if-else are mutually
; exclusive.
;
;CHECK-LABEL: {{^}}test_control_flow_0:
;CHECK-NEXT: ; %main_body
;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
;CHECK-NEXT: s_wqm_b64 exec, exec
;CHECK: %ELSE
;CHECK: s_and_saveexec_b64 [[SAVED:s\[[0-9]+:[0-9]+\]]], [[ORIG]]
;CHECK: store
;CHECK: s_mov_b64 exec, [[SAVED]]
;CHECK: %IF
;CHECK: image_sample
;CHECK: image_sample
define amdgpu_ps float @test_control_flow_0(<8 x i32> inreg %rsrc, <4 x i32> inreg %sampler, i32 %c, i32 %z, float %data) {
main_body:
%cmp = icmp eq i32 %z, 0
br i1 %cmp, label %IF, label %ELSE
IF:
%c.bc = bitcast i32 %c to float
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float %c.bc, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%dtex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> %tex, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%data.if = extractelement <4 x float> %dtex, i32 0
br label %END
ELSE:
call void @llvm.amdgcn.buffer.store.f32(float %data, <4 x i32> undef, i32 %c, i32 0, i1 0, i1 0)
br label %END
END:
%r = phi float [ %data.if, %IF ], [ %data, %ELSE ]
ret float %r
}
; Reverse branch order compared to the previous test.
;
;CHECK-LABEL: {{^}}test_control_flow_1:
;CHECK-NEXT: ; %main_body
;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
;CHECK-NEXT: s_wqm_b64 exec, exec
;CHECK: %IF
;CHECK: image_sample
;CHECK: image_sample
;CHECK: %Flow
;CHECK-NEXT: s_or_saveexec_b64 [[SAVED:s\[[0-9]+:[0-9]+\]]],
;CHECK-NEXT: s_and_b64 exec, exec, [[ORIG]]
;CHECK-NEXT: s_and_b64 [[SAVED]], exec, [[SAVED]]
;CHECK-NEXT: s_xor_b64 exec, exec, [[SAVED]]
;CHECK-NEXT: mask branch [[END_BB:BB[0-9]+_[0-9]+]]
;CHECK-NEXT: BB{{[0-9]+_[0-9]+}}: ; %ELSE
;CHECK: store_dword
;CHECK: [[END_BB]]: ; %END
;CHECK: s_or_b64 exec, exec,
;CHECK: v_mov_b32_e32 v0
;CHECK: ; return
define amdgpu_ps float @test_control_flow_1(<8 x i32> inreg %rsrc, <4 x i32> inreg %sampler, i32 %c, i32 %z, float %data) {
main_body:
%cmp = icmp eq i32 %z, 0
br i1 %cmp, label %ELSE, label %IF
IF:
%c.bc = bitcast i32 %c to float
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float %c.bc, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%dtex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> %tex, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%data.if = extractelement <4 x float> %dtex, i32 0
br label %END
ELSE:
call void @llvm.amdgcn.buffer.store.f32(float %data, <4 x i32> undef, i32 %c, i32 0, i1 0, i1 0)
br label %END
END:
%r = phi float [ %data.if, %IF ], [ %data, %ELSE ]
ret float %r
}
; Check that branch conditions are properly marked as needing WQM...
;
;CHECK-LABEL: {{^}}test_control_flow_2:
;CHECK-NEXT: ; %main_body
;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
;CHECK-NEXT: s_wqm_b64 exec, exec
;CHECK: s_and_b64 exec, exec, [[ORIG]]
;CHECK: store
;CHECK: s_wqm_b64 exec, exec
;CHECK: load
;CHECK: s_and_b64 exec, exec, [[ORIG]]
;CHECK: store
;CHECK: s_wqm_b64 exec, exec
;CHECK: v_cmp
define amdgpu_ps <4 x float> @test_control_flow_2(<8 x i32> inreg %rsrc, <4 x i32> inreg %sampler, <3 x i32> %idx, <2 x float> %data, i32 %coord) {
main_body:
%idx.1 = extractelement <3 x i32> %idx, i32 0
%data.1 = extractelement <2 x float> %data, i32 0
call void @llvm.amdgcn.buffer.store.f32(float %data.1, <4 x i32> undef, i32 %idx.1, i32 0, i1 0, i1 0)
; The load that determines the branch (and should therefore be WQM) is
; surrounded by stores that require disabled WQM.
%idx.2 = extractelement <3 x i32> %idx, i32 1
%z = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 %idx.2, i32 0, i1 0, i1 0)
%idx.3 = extractelement <3 x i32> %idx, i32 2
%data.3 = extractelement <2 x float> %data, i32 1
call void @llvm.amdgcn.buffer.store.f32(float %data.3, <4 x i32> undef, i32 %idx.3, i32 0, i1 0, i1 0)
%cc = fcmp ogt float %z, 0.0
br i1 %cc, label %IF, label %ELSE
IF:
%coord.IF = mul i32 %coord, 3
br label %END
ELSE:
%coord.ELSE = mul i32 %coord, 4
br label %END
END:
%coord.END = phi i32 [ %coord.IF, %IF ], [ %coord.ELSE, %ELSE ]
%coord.END.bc = bitcast i32 %coord.END to float
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float %coord.END.bc, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
ret <4 x float> %tex
}
; ... but only if they really do need it.
;
;CHECK-LABEL: {{^}}test_control_flow_3:
;CHECK-NEXT: ; %main_body
;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
;CHECK-NEXT: s_wqm_b64 exec, exec
;CHECK: image_sample
;CHECK: s_and_b64 exec, exec, [[ORIG]]
;CHECK: image_sample
;CHECK-DAG: v_cmp
;CHECK-DAG: store
define amdgpu_ps float @test_control_flow_3(<8 x i32> inreg %rsrc, <4 x i32> inreg %sampler, i32 %idx, float %coord) {
main_body:
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float %coord, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%dtex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> %tex, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%dtex.1 = extractelement <4 x float> %dtex, i32 0
call void @llvm.amdgcn.buffer.store.f32(float %dtex.1, <4 x i32> undef, i32 %idx, i32 0, i1 0, i1 0)
%cc = fcmp ogt float %dtex.1, 0.0
br i1 %cc, label %IF, label %ELSE
IF:
%tex.IF = fmul float %dtex.1, 3.0
br label %END
ELSE:
%tex.ELSE = fmul float %dtex.1, 4.0
br label %END
END:
%tex.END = phi float [ %tex.IF, %IF ], [ %tex.ELSE, %ELSE ]
ret float %tex.END
}
; Another test that failed at some point because of terminator handling.
;
;CHECK-LABEL: {{^}}test_control_flow_4:
;CHECK-NEXT: ; %main_body
;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
;CHECK-NEXT: s_wqm_b64 exec, exec
;CHECK: %IF
;CHECK: s_and_saveexec_b64 [[SAVE:s\[[0-9]+:[0-9]+\]]], [[ORIG]]
;CHECK: load
;CHECK: store
;CHECK: s_mov_b64 exec, [[SAVE]]
;CHECK: %END
;CHECK: image_sample
;CHECK: image_sample
define amdgpu_ps <4 x float> @test_control_flow_4(<8 x i32> inreg %rsrc, <4 x i32> inreg %sampler, float %coord, i32 %y, float %z) {
main_body:
%cond = icmp eq i32 %y, 0
br i1 %cond, label %IF, label %END
IF:
%data = call float @llvm.amdgcn.buffer.load.f32(<4 x i32> undef, i32 0, i32 0, i1 0, i1 0)
call void @llvm.amdgcn.buffer.store.f32(float %data, <4 x i32> undef, i32 1, i32 0, i1 0, i1 0)
br label %END
END:
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float %coord, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%dtex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> %tex, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
ret <4 x float> %dtex
}
; Kill is performed in WQM mode so that uniform kill behaves correctly ...
;
;CHECK-LABEL: {{^}}test_kill_0:
;CHECK-NEXT: ; %main_body
;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
;CHECK-NEXT: s_wqm_b64 exec, exec
;CHECK: s_and_b64 exec, exec, [[ORIG]]
;CHECK: image_sample
;CHECK: buffer_store_dword
;CHECK: s_wqm_b64 exec, exec
;CHECK: v_cmpx_
;CHECK: s_and_saveexec_b64 [[SAVE:s\[[0-9]+:[0-9]+\]]], [[ORIG]]
;CHECK: buffer_store_dword
;CHECK: s_mov_b64 exec, [[SAVE]]
;CHECK: image_sample
define amdgpu_ps <4 x float> @test_kill_0(<8 x i32> inreg %rsrc, <4 x i32> inreg %sampler, float addrspace(1)* inreg %ptr, <2 x i32> %idx, <2 x float> %data, float %coord, float %coord2, float %z) {
main_body:
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float %coord, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%idx.0 = extractelement <2 x i32> %idx, i32 0
%data.0 = extractelement <2 x float> %data, i32 0
call void @llvm.amdgcn.buffer.store.f32(float %data.0, <4 x i32> undef, i32 %idx.0, i32 0, i1 0, i1 0)
call void @llvm.AMDGPU.kill(float %z)
%idx.1 = extractelement <2 x i32> %idx, i32 1
%data.1 = extractelement <2 x float> %data, i32 1
call void @llvm.amdgcn.buffer.store.f32(float %data.1, <4 x i32> undef, i32 %idx.1, i32 0, i1 0, i1 0)
%tex2 = call <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float %coord2, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%dtex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> %tex2, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%out = fadd <4 x float> %tex, %dtex
ret <4 x float> %out
}
; ... but only if WQM is necessary.
;
; CHECK-LABEL: {{^}}test_kill_1:
; CHECK-NEXT: ; %main_body
; CHECK: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
; CHECK: s_wqm_b64 exec, exec
; CHECK: image_sample
; CHECK: s_and_b64 exec, exec, [[ORIG]]
; CHECK: image_sample
; CHECK: buffer_store_dword
; CHECK-NOT: wqm
; CHECK: v_cmpx_
define amdgpu_ps <4 x float> @test_kill_1(<8 x i32> inreg %rsrc, <4 x i32> inreg %sampler, i32 %idx, float %data, float %coord, float %coord2, float %z) {
main_body:
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float %coord, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%dtex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> %tex, <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
call void @llvm.amdgcn.buffer.store.f32(float %data, <4 x i32> undef, i32 0, i32 0, i1 0, i1 0)
call void @llvm.AMDGPU.kill(float %z)
ret <4 x float> %dtex
}
; Check prolog shaders.
;
; CHECK-LABEL: {{^}}test_prolog_1:
; CHECK: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
; CHECK: s_wqm_b64 exec, exec
; CHECK: v_add_f32_e32 v0,
; CHECK: s_and_b64 exec, exec, [[ORIG]]
define amdgpu_ps float @test_prolog_1(float %a, float %b) #5 {
main_body:
%s = fadd float %a, %b
ret float %s
}
; CHECK-LABEL: {{^}}test_loop_vcc:
; CHECK-NEXT: ; %entry
; CHECK-NEXT: s_mov_b64 [[LIVE:s\[[0-9]+:[0-9]+\]]], exec
; CHECK: s_wqm_b64 exec, exec
; CHECK: s_and_b64 exec, exec, [[LIVE]]
; CHECK: image_store
; CHECK: s_wqm_b64 exec, exec
; CHECK-DAG: v_mov_b32_e32 [[CTR:v[0-9]+]], 0
; CHECK-DAG: v_mov_b32_e32 [[SEVEN:v[0-9]+]], 0x40e00000
; CHECK: [[LOOPHDR:BB[0-9]+_[0-9]+]]: ; %body
; CHECK: v_add_f32_e32 [[CTR]], 2.0, [[CTR]]
; CHECK: v_cmp_gt_f32_e32 vcc, [[CTR]], [[SEVEN]]
; CHECK: s_cbranch_vccz [[LOOPHDR]]
; CHECK: ; %break
; CHECK: ; return
define amdgpu_ps <4 x float> @test_loop_vcc(<4 x float> %in) nounwind {
entry:
call void @llvm.amdgcn.image.store.v4f32.v4i32.v8i32(<4 x float> %in, <4 x i32> undef, <8 x i32> undef, i32 15, i1 0, i1 0, i1 0, i1 0)
br label %loop
loop:
%ctr.iv = phi float [ 0.0, %entry ], [ %ctr.next, %body ]
%c.iv = phi <4 x float> [ %in, %entry ], [ %c.next, %body ]
%cc = fcmp ogt float %ctr.iv, 7.0
br i1 %cc, label %break, label %body
body:
%c.next = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> %c.iv, <8 x i32> undef, <4 x i32> undef, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%ctr.next = fadd float %ctr.iv, 2.0
br label %loop
break:
ret <4 x float> %c.iv
}
; Only intrinsic stores need exact execution -- other stores do not have
; externally visible effects and may require WQM for correctness.
;
; CHECK-LABEL: {{^}}test_alloca:
; CHECK: s_mov_b64 [[LIVE:s\[[0-9]+:[0-9]+\]]], exec
; CHECK: s_wqm_b64 exec, exec
; CHECK: s_and_b64 exec, exec, [[LIVE]]
; CHECK: buffer_store_dword {{v[0-9]+}}, off, {{s\[[0-9]+:[0-9]+\]}}, 0
; CHECK: s_wqm_b64 exec, exec
; CHECK: buffer_store_dword {{v[0-9]+}}, off, {{s\[[0-9]+:[0-9]+\]}}, {{s[0-9]+}} offset:4{{$}}
; CHECK: s_and_b64 exec, exec, [[LIVE]]
; CHECK: buffer_store_dword {{v[0-9]+}}, {{v[0-9]+}}, {{s\[[0-9]+:[0-9]+\]}}, 0 idxen
; CHECK: s_wqm_b64 exec, exec
; CHECK: buffer_load_dword {{v[0-9]+}}, {{v[0-9]+}}, {{s\[[0-9]+:[0-9]+\]}}, {{s[0-9]+}} offen
; CHECK: s_and_b64 exec, exec, [[LIVE]]
; CHECK: image_sample
; CHECK: buffer_store_dwordx4
define amdgpu_ps void @test_alloca(float %data, i32 %a, i32 %idx) nounwind {
entry:
%array = alloca [32 x i32], align 4, addrspace(5)
call void @llvm.amdgcn.buffer.store.f32(float %data, <4 x i32> undef, i32 0, i32 0, i1 0, i1 0)
%s.gep = getelementptr [32 x i32], [32 x i32] addrspace(5)* %array, i32 0, i32 0
store volatile i32 %a, i32 addrspace(5)* %s.gep, align 4
call void @llvm.amdgcn.buffer.store.f32(float %data, <4 x i32> undef, i32 1, i32 0, i1 0, i1 0)
%c.gep = getelementptr [32 x i32], [32 x i32] addrspace(5)* %array, i32 0, i32 %idx
%c = load i32, i32 addrspace(5)* %c.gep, align 4
%c.bc = bitcast i32 %c to float
%t = call <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float %c.bc, <8 x i32> undef, <4 x i32> undef, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
call void @llvm.amdgcn.buffer.store.v4f32(<4 x float> %t, <4 x i32> undef, i32 0, i32 0, i1 0, i1 0)
ret void
}
; Must return to exact at the end of a non-void returning shader,
; otherwise the EXEC mask exported by the epilog will be wrong. This is true
; even if the shader has no kills, because a kill could have happened in a
; previous shader fragment.
;
; CHECK-LABEL: {{^}}test_nonvoid_return:
; CHECK: s_mov_b64 [[LIVE:s\[[0-9]+:[0-9]+\]]], exec
; CHECK: s_wqm_b64 exec, exec
;
; CHECK: s_and_b64 exec, exec, [[LIVE]]
; CHECK-NOT: exec
define amdgpu_ps <4 x float> @test_nonvoid_return() nounwind {
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> undef, <8 x i32> undef, <4 x i32> undef, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%dtex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> %tex, <8 x i32> undef, <4 x i32> undef, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
ret <4 x float> %dtex
}
; CHECK-LABEL: {{^}}test_nonvoid_return_unreachable:
; CHECK: s_mov_b64 [[LIVE:s\[[0-9]+:[0-9]+\]]], exec
; CHECK: s_wqm_b64 exec, exec
;
; CHECK: s_and_b64 exec, exec, [[LIVE]]
; CHECK-NOT: exec
define amdgpu_ps <4 x float> @test_nonvoid_return_unreachable(i32 inreg %c) nounwind {
entry:
%tex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> undef, <8 x i32> undef, <4 x i32> undef, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%dtex = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float> %tex, <8 x i32> undef, <4 x i32> undef, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
%cc = icmp sgt i32 %c, 0
br i1 %cc, label %if, label %else
if:
store volatile <4 x float> %dtex, <4 x float> addrspace(1)* undef
unreachable
else:
ret <4 x float> %dtex
}
; Test awareness that s_wqm_b64 clobbers SCC.
;
; CHECK-LABEL: {{^}}test_scc:
; CHECK: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
; CHECK: s_wqm_b64 exec, exec
; CHECK: s_cmp_
; CHECK-NEXT: s_cbranch_scc
; CHECK: ; %if
; CHECK: s_and_b64 exec, exec, [[ORIG]]
; CHECK: image_sample
; CHECK: ; %else
; CHECK: s_and_b64 exec, exec, [[ORIG]]
; CHECK: image_sample
; CHECK: ; %end
define amdgpu_ps <4 x float> @test_scc(i32 inreg %sel, i32 %idx) #1 {
main_body:
%cc = icmp sgt i32 %sel, 0
br i1 %cc, label %if, label %else
if:
%r.if = call <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float 0.0, <8 x i32> undef, <4 x i32> undef, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
br label %end
else:
%r.else = call <4 x float> @llvm.amdgcn.image.sample.v4f32.v2f32.v8i32(<2 x float> <float 0.0, float bitcast (i32 1 to float)>, <8 x i32> undef, <4 x i32> undef, i32 15, i1 false, i1 false, i1 false, i1 false, i1 false) #0
br label %end
end:
%r = phi <4 x float> [ %r.if, %if ], [ %r.else, %else ]
call void @llvm.amdgcn.buffer.store.f32(float 1.0, <4 x i32> undef, i32 %idx, i32 0, i1 0, i1 0)
ret <4 x float> %r
}
declare void @llvm.amdgcn.exp.f32(i32, i32, float, float, float, float, i1, i1) #1
declare void @llvm.amdgcn.image.store.v4f32.v4i32.v8i32(<4 x float>, <4 x i32>, <8 x i32>, i32, i1, i1, i1, i1) #1
declare void @llvm.amdgcn.buffer.store.f32(float, <4 x i32>, i32, i32, i1, i1) #2
declare void @llvm.amdgcn.buffer.store.v4f32(<4 x float>, <4 x i32>, i32, i32, i1, i1) #2
declare <4 x float> @llvm.amdgcn.image.load.v4f32.v4i32.v8i32(<4 x i32>, <8 x i32>, i32, i1, i1, i1, i1) #3
declare float @llvm.amdgcn.buffer.load.f32(<4 x i32>, i32, i32, i1, i1) #3
declare <4 x float> @llvm.amdgcn.image.sample.v4f32.f32.v8i32(float, <8 x i32>, <4 x i32>, i32, i1, i1, i1, i1, i1) #3
declare <4 x float> @llvm.amdgcn.image.sample.v4f32.v2f32.v8i32(<2 x float>, <8 x i32>, <4 x i32>, i32, i1, i1, i1, i1, i1) #3
declare <4 x float> @llvm.amdgcn.image.sample.v4f32.v4f32.v8i32(<4 x float>, <8 x i32>, <4 x i32>, i32, i1, i1, i1, i1, i1) #3
declare void @llvm.AMDGPU.kill(float) #1
declare float @llvm.amdgcn.wqm.f32(float) #3
declare i32 @llvm.amdgcn.wqm.i32(i32) #3
[AMDGPU] Add support for Whole Wavefront Mode Summary: Whole Wavefront Wode (WWM) is similar to WQM, except that all of the lanes are always enabled, regardless of control flow. This is required for implementing wavefront reductions in non-uniform control flow, where we need to use the inactive lanes to propagate intermediate results, so they need to be enabled. We need to propagate WWM to uses (unless they're explicitly marked as exact) so that they also propagate intermediate results correctly. We do the analysis and exec mask munging during the WQM pass, since there are interactions with WQM for things that require both WQM and WWM. For simplicity, WWM is entirely block-local -- blocks are never WWM on entry or exit of a block, and WWM is not propagated to the block level. This means that computations involving WWM cannot involve control flow, but we only ever plan to use WWM for a few limited purposes (none of which involve control flow) anyways. Shaders can ask for WWM using the @llvm.amdgcn.wwm intrinsic. There isn't yet a way to turn WWM off -- that will be added in a future change. Finally, it turns out that turning on inactive lanes causes a number of problems with register allocation. While the best long-term solution seems like teaching LLVM's register allocator about predication, for now we need to add some hacks to prevent ourselves from getting into trouble due to constraints that aren't currently expressed in LLVM. For the gory details, see the comments at the top of SIFixWWMLiveness.cpp. Reviewers: arsenm, nhaehnle, tpr Subscribers: kzhuravl, wdng, mgorny, yaxunl, dstuttard, t-tye, llvm-commits Differential Revision: https://reviews.llvm.org/D35524 llvm-svn: 310087
2017-08-05 02:36:52 +08:00
declare float @llvm.amdgcn.wwm.f32(float) #3
declare i32 @llvm.amdgcn.wwm.i32(i32) #3
declare i32 @llvm.amdgcn.set.inactive.i32(i32, i32) #4
[AMDGPU] Add support for Whole Wavefront Mode Summary: Whole Wavefront Wode (WWM) is similar to WQM, except that all of the lanes are always enabled, regardless of control flow. This is required for implementing wavefront reductions in non-uniform control flow, where we need to use the inactive lanes to propagate intermediate results, so they need to be enabled. We need to propagate WWM to uses (unless they're explicitly marked as exact) so that they also propagate intermediate results correctly. We do the analysis and exec mask munging during the WQM pass, since there are interactions with WQM for things that require both WQM and WWM. For simplicity, WWM is entirely block-local -- blocks are never WWM on entry or exit of a block, and WWM is not propagated to the block level. This means that computations involving WWM cannot involve control flow, but we only ever plan to use WWM for a few limited purposes (none of which involve control flow) anyways. Shaders can ask for WWM using the @llvm.amdgcn.wwm intrinsic. There isn't yet a way to turn WWM off -- that will be added in a future change. Finally, it turns out that turning on inactive lanes causes a number of problems with register allocation. While the best long-term solution seems like teaching LLVM's register allocator about predication, for now we need to add some hacks to prevent ourselves from getting into trouble due to constraints that aren't currently expressed in LLVM. For the gory details, see the comments at the top of SIFixWWMLiveness.cpp. Reviewers: arsenm, nhaehnle, tpr Subscribers: kzhuravl, wdng, mgorny, yaxunl, dstuttard, t-tye, llvm-commits Differential Revision: https://reviews.llvm.org/D35524 llvm-svn: 310087
2017-08-05 02:36:52 +08:00
declare i32 @llvm.amdgcn.mbcnt.lo(i32, i32) #3
declare i32 @llvm.amdgcn.mbcnt.hi(i32, i32) #3
declare <2 x half> @llvm.amdgcn.cvt.pkrtz(float, float) #3
declare void @llvm.amdgcn.exp.compr.v2f16(i32, i32, <2 x half>, <2 x half>, i1, i1) #1
declare float @llvm.amdgcn.interp.p1(float, i32, i32, i32) #2
declare float @llvm.amdgcn.interp.p2(float, float, i32, i32, i32) #2
attributes #1 = { nounwind }
attributes #2 = { nounwind readonly }
attributes #3 = { nounwind readnone }
attributes #4 = { nounwind readnone convergent }
attributes #5 = { "amdgpu-ps-wqm-outputs" }
attributes #6 = { nounwind "InitialPSInputAddr"="2" }