[llvm] [SLP][NFC] Redesign schedule bundle, separate from schedule data, NFC (PR #131625)

[Gaëtan Bossu via llvm-commits]

================
@@ -4200,6 +4203,112 @@ class BoUpSLP {
   }
 #endif
 
+  class ScheduleBundle final : public ScheduleEntity {
+    /// The schedule data for the instructions in the bundle.
+    SmallVector<ScheduleData *> Bundle;
+    /// True if this bundle is valid.
+    bool IsValid = true;
+    /// The TreeEntry that this instruction corresponds to.
+    TreeEntry *TE = nullptr;
+    ScheduleBundle(bool IsValid)
+        : ScheduleEntity(Kind::ScheduleBundle), IsValid(IsValid) {}
+
+  public:
+    ScheduleBundle() : ScheduleEntity(Kind::ScheduleBundle) {}
+    static bool classof(const ScheduleEntity *Entity) {
+      return Entity->getKind() == Kind::ScheduleBundle;
+    }
+
+    /// Verify basic self consistency properties
+    void verify() const {
+      for (const ScheduleData *SD : Bundle) {
+        if (SD->hasValidDependencies()) {
+          assert(SD->getUnscheduledDeps() <= SD->getDependencies() &&
+                 "invariant");
+        } else {
+          assert(SD->getUnscheduledDeps() == SD->getDependencies() &&
+                 "invariant");
+        }
+
+        if (isScheduled()) {
+          assert(SD->hasValidDependencies() && SD->getUnscheduledDeps() == 0 &&
+                 "unexpected scheduled state");
+        }
+      }
+    }
+
+    bool isScheduled() const {
+      return all_of(Bundle,
+                    [](const ScheduleData *SD) { return SD->isScheduled(); });
+    }
+
+    int unscheduledDepsInBundle() const {
+      assert(*this && "bundle must not be empty");
+      int Sum = 0;
+      for (const ScheduleData *BundleMember : Bundle) {
+        if (BundleMember->getUnscheduledDeps() == ScheduleData::InvalidDeps)
+          return ScheduleData::InvalidDeps;
+        Sum += BundleMember->getUnscheduledDeps();
+      }
+      return Sum;
+    }
+
+    /// Returns true if the dependency information has been calculated.
+    /// Note that depenendency validity can vary between instructions within
+    /// a single bundle.
+    bool hasValidDependencies() const {
+      return all_of(Bundle, [](const ScheduleData *SD) {
+        return SD->hasValidDependencies();
+      });
+    }
+
+    /// Returns true if it is ready for scheduling, i.e. it has no more
+    /// unscheduled depending instructions/bundles.
+    bool isReady() const {
+      assert(*this && "bundle must not be empty");
+      return unscheduledDepsInBundle() == 0 && !isScheduled();
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gbossu wrote:

Could `!isScheduled()` be made into a pre-condition?

https://github.com/llvm/llvm-project/pull/131625