[clang] [CIR] Lowering __builtin_stdc_* calls (PR #214931)

[Kunal Dubey via cfe-commits]

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@@ -111,6 +111,45 @@ static RValue emitBuiltinBitOpWithFallback(CIRGenFunction &cgf,
   return RValue::get(builder.createSelect(loc, isZero, fallbackValue, result));
 }
 
+// stdc_{leading,trailing}_{zeros,ones} and stdc_count_ones: counts bits using
+// clz, ctz, or popcount. InvertArg flips the input to count the opposite bit
+// value.
+template <typename Op, typename... Args>
+static RValue emitStdcCountOp(CIRGenFunction &cgf, const CallExpr *e,
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xakep8 wrote:

Added a helper to check and reject the unsupported _BitInt width which now check if the width is supported or not.

https://github.com/llvm/llvm-project/pull/214931