[PATCH] D24285: AMDGPU: Remove code I think is dead

[Matt Arsenault via llvm-commits]

arsenm created this revision.
arsenm added a reviewer: tstellarAMD.
arsenm added subscribers: llvm-commits, AMDGPU.
Herald added subscribers: nhaehnle, wdng, arsenm.

As far as I can tell, resolveFrameIndex is supposed to be
called with a legal offset, so inserting an add shouldn't be
necessary.

https://reviews.llvm.org/D24285

Files:
  lib/Target/AMDGPU/SIRegisterInfo.cpp

Index: lib/Target/AMDGPU/SIRegisterInfo.cpp
===================================================================
--- lib/Target/AMDGPU/SIRegisterInfo.cpp
+++ lib/Target/AMDGPU/SIRegisterInfo.cpp
@@ -353,34 +353,10 @@
 
   MachineOperand *OffsetOp = TII->getNamedOperand(MI, AMDGPU::OpName::offset);
   int64_t NewOffset = OffsetOp->getImm() + Offset;
-  if (isUInt<12>(NewOffset)) {
-    // If we have a legal offset, fold it directly into the instruction.
-    FIOp->ChangeToRegister(BaseReg, false);
-    OffsetOp->setImm(NewOffset);
-    return;
-  }
-
-  // The offset is not legal, so we must insert an add of the offset.
-  MachineRegisterInfo &MRI = MF->getRegInfo();
-  unsigned NewReg = MRI.createVirtualRegister(&AMDGPU::VGPR_32RegClass);
-  DebugLoc DL = MI.getDebugLoc();
-
-  assert(Offset != 0 && "Non-zero offset expected");
-
-  unsigned UnusedCarry = MRI.createVirtualRegister(&AMDGPU::SReg_64RegClass);
-  unsigned OffsetReg = MRI.createVirtualRegister(&AMDGPU::SReg_32RegClass);
-
-  // In the case the instruction already had an immediate offset, here only
-  // the requested new offset is added because we are leaving the original
-  // immediate in place.
-  BuildMI(*MBB, MI, DL, TII->get(AMDGPU::S_MOV_B32), OffsetReg)
-    .addImm(Offset);
-  BuildMI(*MBB, MI, DL, TII->get(AMDGPU::V_ADD_I32_e64), NewReg)
-    .addReg(UnusedCarry, RegState::Define | RegState::Dead)
-    .addReg(OffsetReg, RegState::Kill)
-    .addReg(BaseReg);
+  assert(isUInt<12>(NewOffset) && "offset should be legal");
 
-  FIOp->ChangeToRegister(NewReg, false);
+  FIOp->ChangeToRegister(BaseReg, false);
+  OffsetOp->setImm(NewOffset);
 }
 
 bool SIRegisterInfo::isFrameOffsetLegal(const MachineInstr *MI,


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