Implement __builtin_constant_p

1 files changed, 6 insertions, 0 deletions

diff --git a/expr.c b/expr.c
index 4dd16a8..b6e7bbc 100644
--- a/expr.c
+++ b/expr.c
@@ -405,6 +405,8 @@ primaryexpr(struct scope *s)
 	return e;
 }
 
+static struct expression *condexpr(struct scope *);
+
 static struct expression *
 builtinfunc(struct scope *s, enum builtinkind kind)
 {
@@ -419,6 +421,10 @@ builtinfunc(struct scope *s, enum builtinkind kind)
 		e->builtin.kind = BUILTINALLOCA;
 		e->builtin.arg = exprconvert(assignexpr(s), &typeulong);
 		break;
+	case BUILTINCONSTANTP:
+		/* XXX: does this need to consider address constants? */
+		e = mkconstexpr(&typeint, eval(condexpr(s))->kind == EXPRCONST);
+		break;
 	case BUILTININFF:
 		e = mkexpr(EXPRCONST, &typefloat, 0);
 		/* TODO: use INFINITY here when we can handle musl's math.h */