[PATCH] D46570: [AMDGPU] Optimzed old value for dpp if unused

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

rampitec created this revision.
rampitec added reviewers: kzhuravl, b-sumner, nhaehnle.
Herald added subscribers: t-tye, tpr, dstuttard, yaxunl, wdng, arsenm.

https://reviews.llvm.org/D46570

Files:
  lib/Target/AMDGPU/SIISelLowering.cpp
  test/CodeGen/AMDGPU/llvm.amdgcn.update.dpp.ll


Index: test/CodeGen/AMDGPU/llvm.amdgcn.update.dpp.ll
===================================================================
--- test/CodeGen/AMDGPU/llvm.amdgcn.update.dpp.ll
+++ test/CodeGen/AMDGPU/llvm.amdgcn.update.dpp.ll
@@ -1,13 +1,34 @@
-; RUN: llc -march=amdgcn -mcpu=tonga -mattr=-flat-for-global -verify-machineinstrs -show-mc-encoding < %s | FileCheck -check-prefix=VI -check-prefix=VI-OPT %s
-; RUN: llc -O0 -march=amdgcn -mcpu=tonga -mattr=-flat-for-global -verify-machineinstrs -show-mc-encoding < %s | FileCheck -check-prefix=VI -check-prefix=VI-NOOPT %s
+; RUN: llc -march=amdgcn -mcpu=tonga -mattr=-flat-for-global -verify-machineinstrs < %s | FileCheck --check-prefixes=GCN,GFX8 %s
 
-; VI-LABEL: {{^}}dpp_test:
-; VI: v_mov_b32_e32 v0, s{{[0-9]+}}
-; VI: v_mov_b32_e32 v1, s{{[0-9]+}}
-; VI: s_nop 1
-; VI: v_mov_b32_dpp v0, v1 quad_perm:[1,0,0,0] row_mask:0x1 bank_mask:0x1 bound_ctrl:0 ; encoding: [0xfa,0x02,0x00,0x7e,0x01,0x01,0x08,0x11]
+; GCN-LABEL: {{^}}dpp_test:
+; GCN: v_mov_b32_e32 [[DST:v[0-9]+]], s{{[0-9]+}}
+; GCN: v_mov_b32_e32 [[SRC:v[0-9]+]], s{{[0-9]+}}
+; GCN: s_nop 1
+; GCN: v_mov_b32_dpp [[DST]], [[SRC]] quad_perm:[1,0,0,0] row_mask:0x1 bank_mask:0x1{{$}}
 define amdgpu_kernel void @dpp_test(i32 addrspace(1)* %out, i32 %in1, i32 %in2) {
-  %tmp0 = call i32 @llvm.amdgcn.update.dpp.i32(i32 %in1, i32 %in2, i32 1, i32 1, i32 1, i1 1) #0
+  %tmp0 = call i32 @llvm.amdgcn.update.dpp.i32(i32 %in1, i32 %in2, i32 1, i32 1, i32 1, i1 0) #0
+  store i32 %tmp0, i32 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}dpp_test_bc:
+; GCN: v_mov_b32_e32 [[DST:v[0-9]+]], s{{[0-9]+}}
+; GCN: v_mov_b32_e32 [[SRC:v[0-9]+]], s{{[0-9]+}}
+; GCN: s_nop 1
+; GCN: v_mov_b32_dpp [[DST]], [[SRC]] quad_perm:[2,0,0,0] row_mask:0x1 bank_mask:0x1 bound_ctrl:0{{$}}
+define amdgpu_kernel void @dpp_test_bc(i32 addrspace(1)* %out, i32 %in1, i32 %in2) {
+  %tmp0 = call i32 @llvm.amdgcn.update.dpp.i32(i32 %in1, i32 %in2, i32 2, i32 1, i32 1, i1 1) #0
+  store i32 %tmp0, i32 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}dpp_noold_test:
+; GCN-NOT: v_mov_b32_e32
+; GCN:     v_mov_b32_e32 [[SRC:v[0-9]+]], s{{[0-9]+}}
+; GCN:     s_nop 1
+; GCN:     v_mov_b32_dpp v{{[0-9]+}}, [[SRC]] quad_perm:[3,0,0,0] row_mask:0xf bank_mask:0xf bound_ctrl:0{{$}}
+define amdgpu_kernel void @dpp_noold_test(i32 addrspace(1)* %out, i32 %in1, i32 %in2) {
+  %tmp0 = call i32 @llvm.amdgcn.update.dpp.i32(i32 %in1, i32 %in2, i32 3, i32 15, i32 15, i1 1) #0
   store i32 %tmp0, i32 addrspace(1)* %out
   ret void
 }
Index: lib/Target/AMDGPU/SIISelLowering.cpp
===================================================================
--- lib/Target/AMDGPU/SIISelLowering.cpp
+++ lib/Target/AMDGPU/SIISelLowering.cpp
@@ -7399,6 +7399,23 @@
     Ops.push_back(ImpDef.getValue(1));
     return DAG.getMachineNode(Opcode, SDLoc(Node), Node->getVTList(), Ops);
   }
+  case AMDGPU::V_MOV_B32_dpp: {
+    ConstantSDNode *RM = cast<ConstantSDNode>(Node->getOperand(3));
+    ConstantSDNode *BM = cast<ConstantSDNode>(Node->getOperand(4));
+    ConstantSDNode *BC = cast<ConstantSDNode>(Node->getOperand(5));
+    if (!BC->getZExtValue() ||
+        RM->getZExtValue() != 0xf || BM->getZExtValue() != 0xf)
+      break;
+    SDValue Old = Node->getOperand(0);
+    if (Old.isMachineOpcode() && Old.getMachineOpcode() == AMDGPU::IMPLICIT_DEF)
+      break;
+    MachineSDNode *ImpDef = DAG.getMachineNode(TargetOpcode::IMPLICIT_DEF,
+                                               SDLoc(Node), MVT::i32);
+    SmallVector<SDValue, 6> Ops = { SDValue(ImpDef, 0), Node->getOperand(1),
+                                    Node->getOperand(2), SDValue(RM, 0),
+                                    SDValue(BM, 0), SDValue(BC, 0) };
+    return DAG.getMachineNode(Opcode, SDLoc(Node), Node->getVTList(), Ops);
+  }
   default:
     break;
   }


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