[llvm] [ConstraintElim] Add facts implied by llvm.abs (PR #73189)

[Florian Hahn via llvm-commits]

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@@ -984,32 +984,37 @@ void State::addInfoFor(BasicBlock &BB) {
       continue;
     }
 
-    if (match(&I, m_Intrinsic<Intrinsic::ssub_with_overflow>())) {
+    auto *II = dyn_cast<IntrinsicInst>(&I);
+    Intrinsic::ID ID = II ? II->getIntrinsicID() : Intrinsic::not_intrinsic;
+    switch (ID) {
+    case Intrinsic::assume:
+      Value *A, *B;
+      CmpInst::Predicate Pred;
+      if (match(I.getOperand(0), m_ICmp(Pred, m_Value(A), m_Value(B)))) {
+        if (GuaranteedToExecute) {
+          // The assume is guaranteed to execute when BB is entered, hence Cond
+          // holds on entry to BB.
+          WorkList.emplace_back(FactOrCheck::getConditionFact(
+              DT.getNode(I.getParent()), Pred, A, B));
+        } else {
+          WorkList.emplace_back(
+              FactOrCheck::getInstFact(DT.getNode(I.getParent()), &I));
+        }
+      }
+      break;
+    case Intrinsic::ssub_with_overflow:
       WorkList.push_back(
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fhahn wrote:

might be good to add a comment here that we queue ssub_with_overflow for simplification and below we queue the intrinsics to add extra info.

https://github.com/llvm/llvm-project/pull/73189