[llvm] [ConstraintElim] Strengthen flags at the closest dominator of all uses. (PR #220918)

[Yingwei Zheng via llvm-commits]

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@@ -1543,10 +1573,12 @@ void State::addInfoFor(BasicBlock &BB) {
         WorkList.push_back(FactOrCheck::getInstFact(DT.getNode(&BB), BO));
     }
 
-    // Queue instructions whose flags may be strengthened based on the facts
-    // that hold on entry to BB.
+    // Queue instructions whose flags may be strengthened, checked at the
+    // closest point dominating all uses.
     if (canStrengthenFlags(&I))
-      WorkList.push_back(FactOrCheck::getCheck(DT.getNode(&BB), &I));
+      if (Instruction *CommonDom = findCommonDominatorOfUses(I, DT))
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dtcxzyw wrote:

CommonDom should be nonnull.


https://github.com/llvm/llvm-project/pull/220918