[clang] [CIR] Add support for __builtin_assume (PR #144376)

[Sirui Mu via cfe-commits]

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@@ -49,7 +52,43 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
     }
   }
 
+  assert(!cir::MissingFeatures::opCallBuiltin());
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Lancern wrote:

Replaced it with several fine-grained missing feature flags.

https://github.com/llvm/llvm-project/pull/144376