[llvm-branch-commits] [llvm] [HLSL][RootSignature] Implement `ResourceRange` as an `IntervalMap` (PR #140957)

[Deric C. via llvm-branch-commits]

================
@@ -222,6 +222,67 @@ MDNode *MetadataBuilder::BuildDescriptorTableClause(
            });
 }
 
+std::optional<const RangeInfo *>
+ResourceRange::getOverlapping(const RangeInfo &Info) const {
+  IMap::const_iterator Interval = Intervals.find(Info.LowerBound);
+  if (!Interval.valid() || Info.UpperBound < Interval.start())
+    return std::nullopt;
+  return Interval.value();
+}
+
+const RangeInfo *ResourceRange::lookup(uint32_t X) const {
+  return Intervals.lookup(X, nullptr);
+}
+
+std::optional<const RangeInfo *> ResourceRange::insert(const RangeInfo &Info) {
+  uint32_t LowerBound = Info.LowerBound;
+  uint32_t UpperBound = Info.UpperBound;
+
+  std::optional<const RangeInfo *> Res = std::nullopt;
+  IMap::iterator Interval = Intervals.begin();
+
+  while (true) {
+    if (UpperBound < LowerBound)
+      break;
+
+    Interval.advanceTo(LowerBound);
+    if (!Interval.valid()) // No interval found
+      break;
+
+    // Let Interval = [x;y] and [LowerBound;UpperBound] = [a;b] and note that
+    // a <= y implicitly from Intervals.find(LowerBound)
----------------
Icohedron wrote:

```suggestion
    // a <= y implicitly from Interval.advanceTo(LowerBound)
```

https://github.com/llvm/llvm-project/pull/140957