[AMDGPU] Support AMDGPUClamp for bf16 on gfx1250

llvm/lib/Target/AMDGPU/SIISelLowering.cpp

@@ -14179,6 +14179,8 @@ SDValue SITargetLowering::performMinMaxCombine(SDNode *N,
         Op0.getOpcode() == AMDGPUISD::FMAX_LEGACY)) &&
       (VT == MVT::f32 || VT == MVT::f64 ||
        (VT == MVT::f16 && Subtarget->has16BitInsts()) ||
+       (VT == MVT::bf16 && Subtarget->hasBF16PackedInsts()) ||
+       (VT == MVT::v2bf16 && Subtarget->hasBF16PackedInsts()) ||
        (VT == MVT::v2f16 && Subtarget->hasVOP3PInsts())) &&
       Op0.hasOneUse()) {
     if (SDValue Res = performFPMed3ImmCombine(DAG, SDLoc(N), Op0, Op1))

llvm/lib/Target/AMDGPU/SIInstrInfo.cpp

@@ -2509,6 +2509,20 @@ bool SIInstrInfo::expandPostRAPseudo(MachineInstr &MI) const {
     }
     break;
   }
+
+  case AMDGPU::V_MAX_BF16_PSEUDO_e64:
+    assert(ST.hasBF16PackedInsts());
+    MI.setDesc(get(AMDGPU::V_PK_MAX_NUM_BF16));
+    MI.addOperand(MachineOperand::CreateImm(0)); // op_sel
+    MI.addOperand(MachineOperand::CreateImm(0)); // neg_lo
+    MI.addOperand(MachineOperand::CreateImm(0)); // neg_hi
+    auto Op0 = getNamedOperand(MI, AMDGPU::OpName::src0_modifiers);
+    Op0->setImm(Op0->getImm() | SISrcMods::OP_SEL_1);
+    auto Op1 = getNamedOperand(MI, AMDGPU::OpName::src1_modifiers);
+    Op1->setImm(Op1->getImm() | SISrcMods::OP_SEL_1);
+    break;
+  }
+
   return true;
 }
 

llvm/lib/Target/AMDGPU/SIInstrInfo.td

@@ -2865,6 +2865,7 @@ def VOP_F16_F16_I16 : VOPProfile <[f16, f16, i16, untyped]>;
 def VOP_F16_F16_I32 : VOPProfile <[f16, f16, i32, untyped]>;
 def VOP_I16_I16_I16 : VOPProfile <[i16, i16, i16, untyped]>;
 def VOP_I16_I16_I16_ARITH : VOPProfile <[i16, i16, i16, untyped], /*EnableClamp=*/1>;
+def VOP_BF16_BF16_BF16 : VOPProfile <[bf16, bf16, bf16, untyped]>;
 
 def VOP_I16_I16_I16_I16 : VOPProfile <[i16, i16, i16, i16, untyped]>;
 def VOP_F16_F16_F16_F16 : VOPProfile <[f16, f16, f16, f16, untyped]>;

llvm/lib/Target/AMDGPU/SIInstructions.td

@@ -1894,6 +1894,9 @@ let SubtargetPredicate = UseRealTrue16Insts in
 def : ClampPat<V_MAX_F16_t16_e64, f16>;
 let SubtargetPredicate = UseFakeTrue16Insts in
 def : ClampPat<V_MAX_F16_fake16_e64, f16>;
+// FIXME-TRUE16: Pseudo expansion of this won't work with True16.
+let True16Predicate = UseFakeTrue16Insts in
+def : ClampPat<V_MAX_BF16_PSEUDO_e64, bf16>;
 
 let SubtargetPredicate = HasVOP3PInsts in {
 def : GCNPat <
@@ -1903,6 +1906,13 @@ def : GCNPat <
 >;
 }
 
+let SubtargetPredicate = HasBF16PackedInsts in {
+def : GCNPat <
+  (v2bf16 (AMDGPUclamp (VOP3PMods v2bf16:$src0, i32:$src0_modifiers))),
+  (V_PK_MAX_NUM_BF16 $src0_modifiers, $src0,
+                     $src0_modifiers, $src0, DSTCLAMP.ENABLE)
+>;
+} // End SubtargetPredicate = HasBF16PackedInsts
 
 /********** ================================ **********/
 /********** Floating point absolute/negative **********/

llvm/lib/Target/AMDGPU/VOP3PInstructions.td

@@ -1236,6 +1236,12 @@ let isCommutable = 1, isReMaterializable = 1 in {
     defm V_PK_MIN_NUM_BF16 : VOP3PInst<"v_pk_min_num_bf16", VOP3P_Profile<VOP_V2BF16_V2BF16_V2BF16, VOP3_PACKED>, fminnum_like>;
     defm V_PK_MAX_NUM_BF16 : VOP3PInst<"v_pk_max_num_bf16", VOP3P_Profile<VOP_V2BF16_V2BF16_V2BF16, VOP3_PACKED>, fmaxnum_like>;
     defm V_PK_FMA_BF16     : VOP3PInst<"v_pk_fma_bf16", VOP3P_Profile<VOP_V2BF16_V2BF16_V2BF16_V2BF16, VOP3_PACKED>, any_fma>;
+
+    // Scalar pseudo used to emulate AMDGPUClamp.
+    // Expanded to V_PK_MAX_NUM_BF16 with unused high half.
+    // FIXME-TRUE16: Pseudo expansion of this won't work with True16.
+    let True16Predicate = UseFakeTrue16Insts in
+    defm V_MAX_BF16_PSEUDO : VOP3Inst <"v_max_bf16", VOP_BF16_BF16_BF16>;
   }
 } // End isCommutable = 1, isReMaterializable = 1
 

llvm/test/CodeGen/AMDGPU/bf16-math.ll

@@ -323,6 +323,135 @@ define amdgpu_ps void @v_test_max_v2bf16_vl(ptr addrspace(1) %out, <2 x bfloat>
   ret void
 }
 
+define amdgpu_ps bfloat @test_clamp_bf16(bfloat %src) {
+; GCN-LABEL: test_clamp_bf16:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    v_pk_max_num_bf16 v0, v0, v0 clamp
+; GCN-NEXT:    ; return to shader part epilog
+  %max = call bfloat @llvm.maxnum.bf16(bfloat %src, bfloat 0.0)
+  %clamp = call bfloat @llvm.minnum.bf16(bfloat %max, bfloat 1.0)
+  ret bfloat %clamp
+}
+
+define amdgpu_ps bfloat @test_clamp_bf16_s(bfloat inreg %src) {
+; GCN-LABEL: test_clamp_bf16_s:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    v_pk_max_num_bf16 v0, s0, s0 clamp
+; GCN-NEXT:    ; return to shader part epilog
+  %max = call bfloat @llvm.maxnum.bf16(bfloat %src, bfloat 0.0)
+  %clamp = call bfloat @llvm.minnum.bf16(bfloat %max, bfloat 1.0)
+  ret bfloat %clamp
+}
+
+define amdgpu_ps float @test_clamp_v2bf16(<2 x bfloat> %src) {
+; GCN-LABEL: test_clamp_v2bf16:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    v_pk_max_num_bf16 v0, v0, v0 clamp
+; GCN-NEXT:    ; return to shader part epilog
+  %max = call <2 x bfloat> @llvm.maxnum.v2bf16(<2 x bfloat> %src, <2 x bfloat> <bfloat 0.0, bfloat 0.0>)
+  %clamp = call <2 x bfloat> @llvm.minnum.v2bf16(<2 x bfloat> %max, <2 x bfloat> <bfloat 1.0, bfloat 1.0>)
+  %ret = bitcast <2 x bfloat> %clamp to float
+  ret float %ret
+}
+
+define amdgpu_ps float @test_clamp_v2bf16_s(<2 x bfloat> inreg %src) {
+; GCN-LABEL: test_clamp_v2bf16_s:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    v_pk_max_num_bf16 v0, s0, s0 clamp
+; GCN-NEXT:    ; return to shader part epilog
+  %max = call <2 x bfloat> @llvm.maxnum.v2bf16(<2 x bfloat> %src, <2 x bfloat> <bfloat 0.0, bfloat 0.0>)
+  %clamp = call <2 x bfloat> @llvm.minnum.v2bf16(<2 x bfloat> %max, <2 x bfloat> <bfloat 1.0, bfloat 1.0>)
+  %ret = bitcast <2 x bfloat> %clamp to float
+  ret float %ret
+}
+
+define amdgpu_ps bfloat @test_clamp_bf16_folding(bfloat %src) {
+; GCN-LABEL: test_clamp_bf16_folding:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    v_exp_bf16_e64 v0, v0 clamp
+; GCN-NEXT:    ; return to shader part epilog
+  %exp = call bfloat @llvm.exp2.bf16(bfloat %src)
+  %max = call bfloat @llvm.maxnum.bf16(bfloat %exp, bfloat 0.0)
+  %clamp = call bfloat @llvm.minnum.bf16(bfloat %max, bfloat 1.0)
+  ret bfloat %clamp
+}
+
+define amdgpu_ps float @test_clamp_v2bf16_folding(<2 x bfloat> %src0, <2 x bfloat> %src1) {
+; GCN-LABEL: test_clamp_v2bf16_folding:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    v_pk_mul_bf16 v0, v0, v1 clamp
+; GCN-NEXT:    ; return to shader part epilog
+  %mul = fmul <2 x bfloat> %src0, %src1
+  %max = call <2 x bfloat> @llvm.maxnum.v2bf16(<2 x bfloat> %mul, <2 x bfloat> <bfloat 0.0, bfloat 0.0>)
+  %clamp = call <2 x bfloat> @llvm.minnum.v2bf16(<2 x bfloat> %max, <2 x bfloat> <bfloat 1.0, bfloat 1.0>)
+  %ret = bitcast <2 x bfloat> %clamp to float
+  ret float %ret
+}
+
+define amdgpu_ps void @v_test_mul_add_v2bf16_vvv(ptr addrspace(1) %out, <2 x bfloat> %a, <2 x bfloat> %b, <2 x bfloat> %c) {
+; GCN-LABEL: v_test_mul_add_v2bf16_vvv:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    v_pk_fma_bf16 v2, v2, v3, v4
+; GCN-NEXT:    global_store_b32 v[0:1], v2, off
+; GCN-NEXT:    s_endpgm
+  %mul = fmul contract <2 x bfloat> %a, %b
+  %add = fadd contract <2 x bfloat> %mul, %c
+  store <2 x bfloat> %add, ptr addrspace(1) %out
+  ret void
+}
+
+define amdgpu_ps void @v_test_mul_add_v2bf16_vss(ptr addrspace(1) %out, <2 x bfloat> %a, <2 x bfloat> inreg %b, <2 x bfloat> inreg %c) {
+; GCN-LABEL: v_test_mul_add_v2bf16_vss:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    v_pk_fma_bf16 v2, v2, s0, s1
+; GCN-NEXT:    global_store_b32 v[0:1], v2, off
+; GCN-NEXT:    s_endpgm
+  %mul = fmul contract <2 x bfloat> %a, %b
+  %add = fadd contract <2 x bfloat> %mul, %c
+  store <2 x bfloat> %add, ptr addrspace(1) %out
+  ret void
+}
+
+define amdgpu_ps void @v_test_mul_add_v2bf16_sss(ptr addrspace(1) %out, <2 x bfloat> inreg %a, <2 x bfloat> inreg %b, <2 x bfloat> inreg %c) {
+; GCN-LABEL: v_test_mul_add_v2bf16_sss:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    v_mov_b32_e32 v2, s2
+; GCN-NEXT:    s_delay_alu instid0(VALU_DEP_1)
+; GCN-NEXT:    v_pk_fma_bf16 v2, s0, s1, v2
+; GCN-NEXT:    global_store_b32 v[0:1], v2, off
+; GCN-NEXT:    s_endpgm
+  %mul = fmul contract <2 x bfloat> %a, %b
+  %add = fadd contract <2 x bfloat> %mul, %c
+  store <2 x bfloat> %add, ptr addrspace(1) %out
+  ret void
+}
+
+define amdgpu_ps void @v_test_mul_add_v2bf16_vsc(ptr addrspace(1) %out, <2 x bfloat> %a, <2 x bfloat> inreg %b) {
+; GCN-LABEL: v_test_mul_add_v2bf16_vsc:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    v_pk_fma_bf16 v2, v2, s0, 0.5 op_sel_hi:[1,1,0]
+; GCN-NEXT:    global_store_b32 v[0:1], v2, off
+; GCN-NEXT:    s_endpgm
+  %mul = fmul contract <2 x bfloat> %a, %b
+  %add = fadd contract <2 x bfloat> %mul, <bfloat 0.5, bfloat 0.5>
+  store <2 x bfloat> %add, ptr addrspace(1) %out
+  ret void
+}
+
+define amdgpu_ps void @v_test_mul_add_v2bf16_vll(ptr addrspace(1) %out, <2 x bfloat> %a) {
+; GCN-LABEL: v_test_mul_add_v2bf16_vll:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    s_mov_b32 s0, 0x43484000
+; GCN-NEXT:    s_delay_alu instid0(SALU_CYCLE_1)
+; GCN-NEXT:    v_pk_fma_bf16 v2, 0x42c83f80, v2, s0
+; GCN-NEXT:    global_store_b32 v[0:1], v2, off
+; GCN-NEXT:    s_endpgm
+  %mul = fmul contract <2 x bfloat> %a, <bfloat 1.0, bfloat 100.0>
+  %add = fadd contract <2 x bfloat> %mul, <bfloat 2.0, bfloat 200.0>
+  store <2 x bfloat> %add, ptr addrspace(1) %out
+  ret void
+}
+
 define amdgpu_ps void @v_test_fma_v2bf16_vvv(ptr addrspace(1) %out, <2 x bfloat> %a, <2 x bfloat> %b, <2 x bfloat> %c) {
 ; GCN-LABEL: v_test_fma_v2bf16_vvv:
 ; GCN:       ; %bb.0:
@@ -426,6 +555,8 @@ define amdgpu_ps void @llvm_exp2_bf16_s(ptr addrspace(1) %out, bfloat inreg %src
   ret void
 }
 
+declare bfloat @llvm.minnum.bf16(bfloat, bfloat)
+declare bfloat @llvm.maxnum.bf16(bfloat, bfloat)
 declare <2 x bfloat> @llvm.minnum.v2bf16(<2 x bfloat> %a, <2 x bfloat> %b)
 declare <2 x bfloat> @llvm.maxnum.v2bf16(<2 x bfloat> %a, <2 x bfloat> %b)
 declare <2 x bfloat> @llvm.fma.v2bf16(<2 x bfloat>, <2 x bfloat>, <2 x bfloat>)