[llvm] [NFC] Reduce copies created of ConstantRange when getting ConstantRangeAttributes. (PR #90335)

[Andreas Jonson via llvm-commits]

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@@ -2199,8 +2199,8 @@ class CallBase : public Instruction {
   FPClassTest getParamNoFPClass(unsigned i) const;
 
   /// If this return value has a range attribute, return the value range of the
-  /// argument. Otherwise, std::nullopt is returned.
-  std::optional<ConstantRange> getRange() const;
+  /// argument. Otherwise, nullptr is returned.
+  const ConstantRange *getRange() const;
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andjo403 wrote:

I'm not sure that I understand this comment, the intersect methods seems to works on `const ConstantRange*` as it is e.g.
`ConstantRange intersectWith(const ConstantRange &CR, PreferredRangeType Type = Smallest) const;` 
or was there something else that you was thinking about?

https://github.com/llvm/llvm-project/pull/90335