[PATCH] D26099: AMDGPU: Stop creating unused virtual registers

[Matt Arsenault via llvm-commits]

arsenm created this revision.
arsenm added a subscriber: llvm-commits.
Herald added a reviewer: tstellarAMD.
Herald added subscribers: tony-tye, yaxunl, nhaehnle, wdng, kzhuravl.

These are only used in the spill to VMEM path. Move them to the one use.


https://reviews.llvm.org/D26099

Files:
  lib/Target/AMDGPU/SIRegisterInfo.cpp


Index: lib/Target/AMDGPU/SIRegisterInfo.cpp
===================================================================
--- lib/Target/AMDGPU/SIRegisterInfo.cpp
+++ lib/Target/AMDGPU/SIRegisterInfo.cpp
@@ -503,7 +503,6 @@
   // SubReg carries the "Kill" flag when SubReg == SuperReg.
   unsigned SubKillState = getKillRegState((NumSubRegs == 1) && IsKill);
   for (unsigned i = 0, e = NumSubRegs; i < e; ++i) {
-    unsigned TmpReg = MRI.createVirtualRegister(&AMDGPU::VGPR_32RegClass);
     unsigned SubReg = NumSubRegs == 1 ?
       SuperReg : getSubReg(SuperReg, getSubRegFromChannel(i));
 
@@ -587,6 +586,7 @@
 
       // Spill SGPR to a frame index.
       // TODO: Should VI try to spill to VGPR and then spill to SMEM?
+      unsigned TmpReg = MRI.createVirtualRegister(&AMDGPU::VGPR_32RegClass);
 
       MachineInstrBuilder Mov
         = BuildMI(*MBB, MI, DL, TII->get(AMDGPU::V_MOV_B32_e32), TmpReg)
@@ -656,7 +656,6 @@
   int64_t FrOffset = FrameInfo.getObjectOffset(Index);
 
   for (unsigned i = 0, e = NumSubRegs; i < e; ++i) {
-    unsigned TmpReg = MRI.createVirtualRegister(&AMDGPU::VGPR_32RegClass);
     unsigned SubReg = NumSubRegs == 1 ?
       SuperReg : getSubReg(SuperReg, getSubRegFromChannel(i));
 
@@ -709,6 +708,7 @@
       // Restore SGPR from a stack slot.
       // FIXME: We should use S_LOAD_DWORD here for VI.
 
+      unsigned TmpReg = MRI.createVirtualRegister(&AMDGPU::VGPR_32RegClass);
       unsigned Align = FrameInfo.getObjectAlignment(Index);
       unsigned Size = FrameInfo.getObjectSize(Index);
 


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