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

[Nikita Popov 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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nikic wrote:

I'm not sure about this one -- e.g. if we wanted to intersect the range on the call and the declaration, we'd no longer be able to do it with this API...

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