[PATCH] D134951: [CodeGen][RegAllocFast] Add MRI delegate callback to notify VReg spill

[Christudasan Devadasan via Phabricator via llvm-commits]

cdevadas updated this revision to Diff 470902.
cdevadas added a comment.

Rebase after recent changes in D134950 <https://reviews.llvm.org/D134950>.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D134951/new/

https://reviews.llvm.org/D134951

Files:
  llvm/include/llvm/CodeGen/MachineRegisterInfo.h
  llvm/lib/CodeGen/LiveIntervals.cpp
  llvm/lib/CodeGen/LiveRangeEdit.cpp
  llvm/lib/CodeGen/RegAllocFast.cpp


Index: llvm/lib/CodeGen/RegAllocFast.cpp
===================================================================
--- llvm/lib/CodeGen/RegAllocFast.cpp
+++ llvm/lib/CodeGen/RegAllocFast.cpp
@@ -434,6 +434,7 @@
   int FI = getStackSpaceFor(VirtReg);
   LLVM_DEBUG(dbgs() << " to stack slot #" << FI << '\n');
 
+  MRI->noteVirtualRegisterSpill(VirtReg);
   const TargetRegisterClass &RC = *MRI->getRegClass(VirtReg);
   TII->storeRegToStackSlot(*MBB, Before, AssignedReg, Kill, FI, &RC, TRI);
   ++NumStores;
@@ -488,6 +489,7 @@
   LLVM_DEBUG(dbgs() << "Reloading " << printReg(VirtReg, TRI) << " into "
                     << printReg(PhysReg, TRI) << '\n');
   int FI = getStackSpaceFor(VirtReg);
+  MRI->noteVirtualRegisterSpill(VirtReg);
   const TargetRegisterClass &RC = *MRI->getRegClass(VirtReg);
   TII->loadRegFromStackSlot(*MBB, Before, PhysReg, FI, &RC, TRI);
   ++NumLoads;
Index: llvm/lib/CodeGen/LiveRangeEdit.cpp
===================================================================
--- llvm/lib/CodeGen/LiveRangeEdit.cpp
+++ llvm/lib/CodeGen/LiveRangeEdit.cpp
@@ -33,7 +33,7 @@
 
 LiveInterval &LiveRangeEdit::createEmptyIntervalFrom(Register OldReg,
                                                      bool createSubRanges) {
-  Register VReg = MRI.createVirtualRegister(MRI.getRegClass(OldReg));
+  Register VReg = MRI.cloneVirtualRegister(OldReg);
   if (VRM)
     VRM->setIsSplitFromReg(VReg, VRM->getOriginal(OldReg));
 
@@ -53,7 +53,7 @@
 }
 
 Register LiveRangeEdit::createFrom(Register OldReg) {
-  Register VReg = MRI.createVirtualRegister(MRI.getRegClass(OldReg));
+  Register VReg = MRI.cloneVirtualRegister(OldReg);
   if (VRM) {
     VRM->setIsSplitFromReg(VReg, VRM->getOriginal(OldReg));
   }
Index: llvm/lib/CodeGen/LiveIntervals.cpp
===================================================================
--- llvm/lib/CodeGen/LiveIntervals.cpp
+++ llvm/lib/CodeGen/LiveIntervals.cpp
@@ -1743,9 +1743,8 @@
     return;
   LLVM_DEBUG(dbgs() << "  Split " << NumComp << " components: " << LI << '\n');
   Register Reg = LI.reg();
-  const TargetRegisterClass *RegClass = MRI->getRegClass(Reg);
   for (unsigned I = 1; I < NumComp; ++I) {
-    Register NewVReg = MRI->createVirtualRegister(RegClass);
+    Register NewVReg = MRI->cloneVirtualRegister(Reg);
     LiveInterval &NewLI = createEmptyInterval(NewVReg);
     SplitLIs.push_back(&NewLI);
   }
Index: llvm/include/llvm/CodeGen/MachineRegisterInfo.h
===================================================================
--- llvm/include/llvm/CodeGen/MachineRegisterInfo.h
+++ llvm/include/llvm/CodeGen/MachineRegisterInfo.h
@@ -61,6 +61,7 @@
                                               Register SrcReg) {
       MRI_NoteNewVirtualRegister(NewReg);
     }
+    virtual void MRI_NoteVirtualRegisterSpill(Register Reg) {}
   };
 
 private:
@@ -183,6 +184,12 @@
       TheDelegate->MRI_NotecloneVirtualRegister(NewReg, SrcReg);
   }
 
+  /// Callback to notify a virtual register spill/reload.
+  void noteVirtualRegisterSpill(Register Reg) {
+    for (const auto &TheDelegate : TheDelegates)
+      TheDelegate->MRI_NoteVirtualRegisterSpill(Reg);
+  }
+
   //===--------------------------------------------------------------------===//
   // Function State
   //===--------------------------------------------------------------------===//


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