[llvm] [ConstraintElimination] Add additional facts for bitwise AND OR (PR #132124)

[Florian Hahn via llvm-commits]

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@@ -1605,6 +1605,30 @@ void ConstraintInfo::addFact(CmpInst::Predicate Pred, Value *A, Value *B,
                              unsigned NumIn, unsigned NumOut,
                              SmallVectorImpl<StackEntry> &DFSInStack) {
   addFactImpl(Pred, A, B, NumIn, NumOut, DFSInStack, false);
+
+  Value *LHS;
+  Value *RHS;
+  if (match(A, m_Or(m_Value(LHS), m_Value(RHS)))) {
+    // (LHS | RHS >= 0) =>  LHS >= 0 && RHS >= 0
+    // (LHS | RHS > -1) =>  LHS >= 0 && RHS >= 0
+    if ((match(B, m_Zero()) && Pred == CmpInst::ICMP_SGE) ||
+        (match(B, m_AllOnes()) && Pred == CmpInst::ICMP_SGT)) {
+      addFact(CmpInst::ICMP_SGE, LHS, ConstantInt::get(LHS->getType(), 0),
+              NumIn, NumOut, DFSInStack);
+      addFact(CmpInst::ICMP_SGE, RHS, ConstantInt::get(RHS->getType(), 0),
+              NumIn, NumOut, DFSInStack);
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fhahn wrote:

is there benefit of continuing to add the constraint for `A`, `B` below or can we return early? Would be good to ensure sufficient test coverage

https://github.com/llvm/llvm-project/pull/132124