R600/SI: Use bcnt instruction for ctpop

llvm-svn: 210567

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Target/R600/SIInstrInfo.cpp b/llvm/lib/Target/R600/SIInstrInfo.cpp
index dc96434..fdebb2f 100644
--- a/llvm/lib/Target/R600/SIInstrInfo.cpp
+++ b/llvm/lib/Target/R600/SIInstrInfo.cpp
@@ -668,6 +668,7 @@ unsigned SIInstrInfo::getVALUOp(const MachineInstr &MI) {
   case AMDGPU::S_LOAD_DWORDX2_SGPR: return AMDGPU::BUFFER_LOAD_DWORDX2_ADDR64;
   case AMDGPU::S_LOAD_DWORDX4_IMM:
   case AMDGPU::S_LOAD_DWORDX4_SGPR: return AMDGPU::BUFFER_LOAD_DWORDX4_ADDR64;
+  case AMDGPU::S_BCNT1_I32_B32: return AMDGPU::V_BCNT_U32_B32_e32;
   }
 }
 
@@ -1218,6 +1219,10 @@ void SIInstrInfo::moveToVALU(MachineInstr &TopInst) const {
       // 3 to not hit an assertion later in MCInstLower.
       Inst->addOperand(MachineOperand::CreateImm(0));
       Inst->addOperand(MachineOperand::CreateImm(0));
+    } else if (Opcode == AMDGPU::S_BCNT1_I32_B32) {
+      // The VALU version adds the second operand to the result, so insert an
+      // extra 0 operand.
+      Inst->addOperand(MachineOperand::CreateImm(0));
     }
 
     addDescImplicitUseDef(NewDesc, Inst);