[clang] [CIR] Add X86 prefetch builtins (PR #168051)

[Bruno Cardoso Lopes via cfe-commits]

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@@ -540,12 +540,20 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
   }
 
   // Now see if we can emit a target-specific builtin.
-  if (mlir::Value v = emitTargetBuiltinExpr(builtinID, e, returnValue)) {
+  std::optional<mlir::Value> valueOpt =
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bcardosolopes wrote:

See other comment!

https://github.com/llvm/llvm-project/pull/168051