[llvm] IR: introduce CmpInst::PredicateSign (PR #116867)

[Matt Arsenault via llvm-commits]

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@@ -722,6 +722,31 @@ class CmpInst : public Instruction {
                               force_iteration_on_noniterable_enum);
   }
 
+  /// An abstraction over a floating-point predicate, and a pack of an integer
+  /// predicate with samesign information. The getPredicateSign() family of
+  /// functions in ICmpInst construct and return this type. It is also implictly
+  /// constructed with a Predicate, dropping samesign information.
+  class PredicateSign {
+    Predicate Pred;
+    std::optional<bool> HasSameSign;
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arsenm wrote:

Don't see the point of this being optional, it looks redundant with the isIntPredicate assertions 

https://github.com/llvm/llvm-project/pull/116867