[llvm] r246079 - AMDGPU: Don't reprocess instructions when splitting i64 bcnt

[Matt Arsenault via llvm-commits]

Author: arsenm
Date: Wed Aug 26 15:48:04 2015
New Revision: 246079

URL: http://llvm.org/viewvc/llvm-project?rev=246079&view=rev
Log:
AMDGPU: Don't reprocess instructions when splitting i64 bcnt

Modified:
    llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp
    llvm/trunk/test/CodeGen/AMDGPU/ctpop64.ll

Modified: llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp?rev=246079&r1=246078&r2=246079&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp Wed Aug 26 15:48:04 2015
@@ -2513,18 +2513,19 @@ void SIInstrInfo::splitScalar64BitBCNT(S
   MachineOperand SrcRegSub1 = buildExtractSubRegOrImm(MII, MRI, Src, SrcRC,
                                                       AMDGPU::sub1, SrcSubRC);
 
-  MachineInstr *First = BuildMI(MBB, MII, DL, InstDesc, MidReg)
+  BuildMI(MBB, MII, DL, InstDesc, MidReg)
     .addOperand(SrcRegSub0)
     .addImm(0);
 
-  MachineInstr *Second = BuildMI(MBB, MII, DL, InstDesc, ResultReg)
+  BuildMI(MBB, MII, DL, InstDesc, ResultReg)
     .addOperand(SrcRegSub1)
     .addReg(MidReg);
 
   MRI.replaceRegWith(Dest.getReg(), ResultReg);
 
-  Worklist.push_back(First);
-  Worklist.push_back(Second);
+  // We don't need to legalize operands here. src0 for etiher instruction can be
+  // an SGPR, and the second input is unused or determined here.
+  addUsersToMoveToVALUWorklist(ResultReg, MRI, Worklist);
 }
 
 void SIInstrInfo::splitScalar64BitBFE(SmallVectorImpl<MachineInstr *> &Worklist,

Modified: llvm/trunk/test/CodeGen/AMDGPU/ctpop64.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AMDGPU/ctpop64.ll?rev=246079&r1=246078&r2=246079&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AMDGPU/ctpop64.ll (original)
+++ llvm/trunk/test/CodeGen/AMDGPU/ctpop64.ll Wed Aug 26 15:48:04 2015
@@ -36,6 +36,25 @@ define void @v_ctpop_i64(i32 addrspace(1
   ret void
 }
 
+; FIXME: We shouldn't emit the v_mov_b32 0
+; FUNC-LABEL: {{^}}v_ctpop_i64_user:
+; GCN: buffer_load_dwordx2 v{{\[}}[[LOVAL:[0-9]+]]:[[HIVAL:[0-9]+]]{{\]}},
+; GCN: v_bcnt_u32_b32_e64 [[MIDRESULT:v[0-9]+]], v[[LOVAL]], 0
+; SI-NEXT: v_bcnt_u32_b32_e32 [[RESULT:v[0-9]+]], v[[HIVAL]], [[MIDRESULT]]
+; VI-NEXT: v_bcnt_u32_b32_e64 [[RESULT:v[0-9]+]], v[[HIVAL]], [[MIDRESULT]]
+; GCN-DAG: v_mov_b32_e32 v[[ZERO:[0-9]+]], 0{{$}}
+; GCN-DAG: v_or_b32_e32 v[[RESULT_LO:[0-9]+]], s{{[0-9]+}}, [[RESULT]]
+; GCN-DAG: v_or_b32_e32 v[[RESULT_HI:[0-9]+]], s{{[0-9]+}}, v[[ZERO]]
+; GCN: buffer_store_dwordx2 v{{\[}}[[RESULT_LO]]:[[RESULT_HI]]{{\]}}
+; GCN: s_endpgm
+define void @v_ctpop_i64_user(i64 addrspace(1)* noalias %out, i64 addrspace(1)* noalias %in, i64 %s.val) nounwind {
+  %val = load i64, i64 addrspace(1)* %in, align 8
+  %ctpop = call i64 @llvm.ctpop.i64(i64 %val) nounwind readnone
+  %or = or i64 %ctpop, %s.val
+  store i64 %or, i64 addrspace(1)* %out
+  ret void
+}
+
 ; FUNC-LABEL: {{^}}s_ctpop_v2i64:
 ; GCN: s_bcnt1_i32_b64
 ; GCN: s_bcnt1_i32_b64