[llvm] [DA] Simplify runtime predicate collection and extend to all dependence tests (PR #157523)

[Sebastian Pop via llvm-commits]

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@@ -3570,6 +3570,37 @@ SCEVUnionPredicate DependenceInfo::getRuntimeAssumptions() const {
   return SCEVUnionPredicate(Assumptions, *SE);
 }
 
+// getNonRedundantAssumptions - Remove redundant assumptions from the collection
+// and return a SCEVUnionPredicate with the unique assumptions. This ensures
+// that each assumption is only present once and that stronger assumptions imply
+// weaker ones, avoiding unnecessary runtime checks.
+SCEVUnionPredicate DependenceInfo::getNonRedundantAssumptions() const {
+  SmallVector<const SCEVPredicate *, 4> UniqueAssumptions;
+
+  for (const SCEVPredicate *P : Assumptions) {
+    bool Implied = false;
+    for (const SCEVPredicate *Existing : UniqueAssumptions) {
+      if (Existing->implies(P, *SE)) {
+        Implied = true;
+        break;
+      }
+    }
+    if (!Implied) {
+      auto I = UniqueAssumptions.begin();
+      while (I != UniqueAssumptions.end()) {
+        if (P->implies(*I, *SE)) {
+          I = UniqueAssumptions.erase(I);
+        } else {
+          ++I;
+        }
+      }
+      UniqueAssumptions.push_back(P);
+    }
+  }
+
+  return SCEVUnionPredicate(UniqueAssumptions, *SE);
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sebpop wrote:

You are right. Thanks for pointing this out.
I removed the vector of predicates and only rely on SCEVUnionPredicate to collect constraints in minimal non-redundant form.

https://github.com/llvm/llvm-project/pull/157523