[llvm] 50054ba - [CodeGen] LiveRegMatrix: Use allocator through a unique_ptr (#120556)

[via llvm-commits]

Author: Akshat Oke
Date: 2025-01-01T14:54:08+05:30
New Revision: 50054ba2f446c29b46f0fe55e7b8c48b3818a23f

URL: https://github.com/llvm/llvm-project/commit/50054ba2f446c29b46f0fe55e7b8c48b3818a23f
DIFF: https://github.com/llvm/llvm-project/commit/50054ba2f446c29b46f0fe55e7b8c48b3818a23f.diff

LOG: [CodeGen] LiveRegMatrix: Use allocator through a unique_ptr (#120556)

`LIU::Matrix` holds on to a pointer to the allocator in LiveRegMatrix and is left hanging when the allocator moves with the LiveRegMatrix.

This extends the lifetime of the allocator so that it does not get destroyed when moving a LiveRegMatrix object.

Added: 
    

Modified: 
    llvm/include/llvm/CodeGen/LiveRegMatrix.h
    llvm/lib/CodeGen/LiveRegMatrix.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/CodeGen/LiveRegMatrix.h b/llvm/include/llvm/CodeGen/LiveRegMatrix.h
index 486392ca3c49d5..373f4402dd8d64 100644
--- a/llvm/include/llvm/CodeGen/LiveRegMatrix.h
+++ b/llvm/include/llvm/CodeGen/LiveRegMatrix.h
@@ -48,7 +48,7 @@ class LiveRegMatrix {
   unsigned UserTag = 0;
 
   // The matrix is represented as a LiveIntervalUnion per register unit.
-  LiveIntervalUnion::Allocator LIUAlloc;
+  std::unique_ptr<LiveIntervalUnion::Allocator> LIUAlloc;
   LiveIntervalUnion::Array Matrix;
 
   // Cached queries per register unit.
@@ -59,15 +59,12 @@ class LiveRegMatrix {
   unsigned RegMaskVirtReg = 0;
   BitVector RegMaskUsable;
 
-  LiveRegMatrix() = default;
+  LiveRegMatrix()
+      : LIUAlloc(std::make_unique<LiveIntervalUnion::Allocator>()) {};
   void releaseMemory();
 
 public:
-  LiveRegMatrix(LiveRegMatrix &&Other)
-      : TRI(Other.TRI), LIS(Other.LIS), VRM(Other.VRM), UserTag(Other.UserTag),
-        Matrix(std::move(Other.Matrix)), Queries(std::move(Other.Queries)),
-        RegMaskTag(Other.RegMaskTag), RegMaskVirtReg(Other.RegMaskVirtReg),
-        RegMaskUsable(std::move(Other.RegMaskUsable)) {}
+  LiveRegMatrix(LiveRegMatrix &&Other) = default;
 
   void init(MachineFunction &MF, LiveIntervals &LIS, VirtRegMap &VRM);
 

diff  --git a/llvm/lib/CodeGen/LiveRegMatrix.cpp b/llvm/lib/CodeGen/LiveRegMatrix.cpp
index 9744c47d5a8510..3367171a15662f 100644
--- a/llvm/lib/CodeGen/LiveRegMatrix.cpp
+++ b/llvm/lib/CodeGen/LiveRegMatrix.cpp
@@ -66,7 +66,7 @@ void LiveRegMatrix::init(MachineFunction &MF, LiveIntervals &pLIS,
   unsigned NumRegUnits = TRI->getNumRegUnits();
   if (NumRegUnits != Matrix.size())
     Queries.reset(new LiveIntervalUnion::Query[NumRegUnits]);
-  Matrix.init(LIUAlloc, NumRegUnits);
+  Matrix.init(*LIUAlloc, NumRegUnits);
 
   // Make sure no stale queries get reused.
   invalidateVirtRegs();