================
@@ -12354,21 +12354,31 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const
CallExpr *E,
case Builtin::BI__builtin_clzl:
case Builtin::BI__builtin_clzll:
case Builtin::BI__builtin_clzs:
+ case Builtin::BI__builtin_clzg:
case Builtin::BI__lzcnt16: // Microsoft variants of count leading-zeroes
case Builtin::BI__lzcnt:
case Builtin::BI__lzcnt64: {
APSInt Val;
if (!EvaluateInteger(E->getArg(0), Val, Info))
return false;
- // When the argument is 0, the result of GCC builtins is undefined, whereas
- // for Microsoft intrinsics, the result is the bit-width of the argument.
- bool ZeroIsUndefined = BuiltinOp != Builtin::BI__lzcnt16 &&
- BuiltinOp != Builtin::BI__lzcnt &&
- BuiltinOp != Builtin::BI__lzcnt64;
+ if (!Val) {
+ if (BuiltinOp == Builtin::BI__builtin_clzg && E->getNumArgs() > 1) {
+ if (!EvaluateInteger(E->getArg(1), Val, Info))
----------------
efriedma-quic wrote:
This EvaluateInteger call can't be guarded by the `if (!Val)` check: even if we
don't actually use the value of the second argument, we have to evaluate it for
side-effects. We don't want short-circuit the evaluation like for `&&`/`||`.
https://github.com/llvm/llvm-project/pull/86577
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