[clang] [clang][x86][bytecode] Replace interp__builtin_parity/clrsb/bitreverse/ffs with static bool interp__builtin_elementwise_int_unaryop callback (PR #162346)

[Simon Pilgrim via cfe-commits]

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@@ -3209,7 +3182,13 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call,
   case Builtin::BI__builtin_ffs:
   case Builtin::BI__builtin_ffsl:
   case Builtin::BI__builtin_ffsll:
-    return interp__builtin_ffs(S, OpPC, Frame, Call);
+    return interp__builtin_elementwise_int_unaryop(
+        S, OpPC, Call, [](const APSInt &Val) {
+          return APInt(Val.getBitWidth(),
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RKSimon wrote:

Or just check if Val is zero - either is fine

https://github.com/llvm/llvm-project/pull/162346