AMDGPU/SI: use S_MOV_B64 for larger copies in copyPhysReg

[• tstellarAMD]

LGTM.

llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp

SIInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
 
   static const int16_t Sub0_15[] = {
     AMDGPU::sub0, AMDGPU::sub1, AMDGPU::sub2, AMDGPU::sub3,
     AMDGPU::sub4, AMDGPU::sub5, AMDGPU::sub6, AMDGPU::sub7,
     AMDGPU::sub8, AMDGPU::sub9, AMDGPU::sub10, AMDGPU::sub11,
     AMDGPU::sub12, AMDGPU::sub13, AMDGPU::sub14, AMDGPU::sub15,
   };
 
+  static const int16_t Sub0_15_64[] = {
+    AMDGPU::sub0_sub1, AMDGPU::sub2_sub3,
+    AMDGPU::sub4_sub5, AMDGPU::sub6_sub7,
+    AMDGPU::sub8_sub9, AMDGPU::sub10_sub11,
+    AMDGPU::sub12_sub13, AMDGPU::sub14_sub15,
+  };
+
   static const int16_t Sub0_7[] = {
     AMDGPU::sub0, AMDGPU::sub1, AMDGPU::sub2, AMDGPU::sub3,
     AMDGPU::sub4, AMDGPU::sub5, AMDGPU::sub6, AMDGPU::sub7,
   };
 
+  static const int16_t Sub0_7_64[] = {
+    AMDGPU::sub0_sub1, AMDGPU::sub2_sub3,
+    AMDGPU::sub4_sub5, AMDGPU::sub6_sub7,
+  };
+
   static const int16_t Sub0_3[] = {
     AMDGPU::sub0, AMDGPU::sub1, AMDGPU::sub2, AMDGPU::sub3,
   };
 
+  static const int16_t Sub0_3_64[] = {
+    AMDGPU::sub0_sub1, AMDGPU::sub2_sub3,
+  };
+
   static const int16_t Sub0_2[] = {
     AMDGPU::sub0, AMDGPU::sub1, AMDGPU::sub2,
   };
 
   static const int16_t Sub0_1[] = {
     AMDGPU::sub0, AMDGPU::sub1,
   };
 
if (AMDGPU::SReg_32RegClass.contains(DestReg)) {
 
     assert(AMDGPU::SReg_64RegClass.contains(SrcReg));
     BuildMI(MBB, MI, DL, get(AMDGPU::S_MOV_B64), DestReg)
             .addReg(SrcReg, getKillRegState(KillSrc));
     return;
 
   } else if (AMDGPU::SReg_128RegClass.contains(DestReg)) {
     assert(AMDGPU::SReg_128RegClass.contains(SrcReg));
-    Opcode = AMDGPU::S_MOV_B32;
-    SubIndices = Sub0_3;
+    Opcode = AMDGPU::S_MOV_B64;
+    SubIndices = Sub0_3_64;
 
   } else if (AMDGPU::SReg_256RegClass.contains(DestReg)) {
     assert(AMDGPU::SReg_256RegClass.contains(SrcReg));
-    Opcode = AMDGPU::S_MOV_B32;
-    SubIndices = Sub0_7;
+    Opcode = AMDGPU::S_MOV_B64;
+    SubIndices = Sub0_7_64;
 
   } else if (AMDGPU::SReg_512RegClass.contains(DestReg)) {
     assert(AMDGPU::SReg_512RegClass.contains(SrcReg));
-    Opcode = AMDGPU::S_MOV_B32;
-    SubIndices = Sub0_15;
+    Opcode = AMDGPU::S_MOV_B64;
+    SubIndices = Sub0_15_64;
 
   } else if (AMDGPU::VGPR_32RegClass.contains(DestReg)) {
     assert(AMDGPU::VGPR_32RegClass.contains(SrcReg) ||
            AMDGPU::SReg_32RegClass.contains(SrcReg));
     BuildMI(MBB, MI, DL, get(AMDGPU::V_MOV_B32_e32), DestReg)
             .addReg(SrcReg, getKillRegState(KillSrc));
     return;