[llvm] [ValueTracking] Use `SimplifyQuery` in `isKnownNonEqual` (PR #124942)

[Nikita Popov via llvm-commits]

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@@ -1349,8 +1349,10 @@ AliasResult BasicAAResult::aliasGEP(
     const VariableGEPIndex &Var1 = DecompGEP1.VarIndices[1];
     if (Var0.hasNegatedScaleOf(Var1) && Var0.Val.TruncBits == 0 &&
         Var0.Val.hasSameCastsAs(Var1.Val) && !AAQI.MayBeCrossIteration &&
-        isKnownNonEqual(Var0.Val.V, Var1.Val.V, DL, &AC, /* CxtI */ nullptr,
-                        DT))
+        isKnownNonEqual(Var0.Val.V, Var1.Val.V,
+                        SimplifyQuery(DL, DT, &AC, /*CxtI=*/Var0.CxtI
+                                                       ? Var0.CxtI
+                                                       : Var1.CxtI)))
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nikic wrote:

This was actually using a null context instruction intentionally, to avoid order-dependence. But due to the implicit context, it ended up not mattering, and now things rely on it... It's okay for now, keeping symmetry in this code is not super important.

https://github.com/llvm/llvm-project/pull/124942