[llvm] [LLVM] Adjust argument passing for `APInt`. NFC. (PR #81814)

[Matt Arsenault via llvm-commits]

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@@ -843,9 +843,9 @@ struct bind_const_intval_ty {
 /// Match a specified integer value or vector of all elements of that
 /// value.
 template <bool AllowUndefs> struct specific_intval {
-  APInt Val;
+  const APInt &Val;
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arsenm wrote:

It only needs to be alive through the m_SpecificInt call where the temporary would be created in the match expression 

https://github.com/llvm/llvm-project/pull/81814