[PATCH] D95489: [AMDGPU] Do not reassign spilled registers

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

rampitec updated this revision to Diff 319651.
rampitec edited the summary of this revision.
rampitec added a comment.

Refuse to reassign any registers which are result of an LI split.
I doubt I can create a proper test though.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D95489/new/

https://reviews.llvm.org/D95489

Files:
  llvm/lib/Target/AMDGPU/GCNNSAReassign.cpp
  llvm/lib/Target/AMDGPU/GCNRegBankReassign.cpp


Index: llvm/lib/Target/AMDGPU/GCNRegBankReassign.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/GCNRegBankReassign.cpp
+++ llvm/lib/Target/AMDGPU/GCNRegBankReassign.cpp
@@ -471,6 +471,12 @@
   if (Reg.isPhysical() || !VRM->isAssignedReg(Reg))
     return false;
 
+  // InlineSpiller does not call LRM::assign() after an LI split leaving it
+  // in an incosistent state, so we cannot call LRM::unassign(). Skip reassign
+  // if a register has originated from such split.
+  if (VRM->getPreSplitReg(Reg))
+    return false;
+
   const MachineInstr *Def = MRI->getUniqueVRegDef(Reg);
 
   Register PhysReg = VRM->getPhys(Reg);
Index: llvm/lib/Target/AMDGPU/GCNNSAReassign.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/GCNNSAReassign.cpp
+++ llvm/lib/Target/AMDGPU/GCNNSAReassign.cpp
@@ -190,6 +190,12 @@
       if (MRI->getRegClass(Reg) != &AMDGPU::VGPR_32RegClass || Op.getSubReg())
         return NSA_Status::FIXED;
 
+      // InlineSpiller does not call LRM::assign() after an LI split leaving
+      // it in an incosistent state, so we cannot call LRM::unassign().
+      // Skip reassign if a register has originated from such split.
+      if (VRM->getPreSplitReg(Reg))
+        return NSA_Status::FIXED;
+
       const MachineInstr *Def = MRI->getUniqueVRegDef(Reg);
 
       if (Def && Def->isCopy() && Def->getOperand(1).getReg() == PhysReg)


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