[llvm] [TRI] Remove reserved registers in getRegPressureSetLimit (PR #118787)

[Craig Topper via llvm-commits]

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@@ -195,40 +195,3 @@ void RegisterClassInfo::compute(const TargetRegisterClass *RC) const {
   // RCI is now up-to-date.
   RCI.Tag = Tag;
 }
-
-/// This is not accurate because two overlapping register sets may have some
-/// nonoverlapping reserved registers. However, computing the allocation order
-/// for all register classes would be too expensive.
-unsigned RegisterClassInfo::computePSetLimit(unsigned Idx) const {
-  const TargetRegisterClass *RC = nullptr;
-  unsigned NumRCUnits = 0;
-  for (const TargetRegisterClass *C : TRI->regclasses()) {
-    const int *PSetID = TRI->getRegClassPressureSets(C);
-    for (; *PSetID != -1; ++PSetID) {
-      if ((unsigned)*PSetID == Idx)
-        break;
-    }
-    if (*PSetID == -1)
-      continue;
-
-    // Found a register class that counts against this pressure set.
-    // For efficiency, only compute the set order for the largest set.
-    unsigned NUnits = TRI->getRegClassWeight(C).WeightLimit;
-    if (!RC || NUnits > NumRCUnits) {
-      RC = C;
-      NumRCUnits = NUnits;
-    }
-  }
-  assert(RC && "Failed to find register class");
-  compute(RC);
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topperc wrote:

Oh, I see its still called from RegClassInfo::get

https://github.com/llvm/llvm-project/pull/118787