isl_test.c: test_ast: avoid invalid access on error

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>

diff --git a/isl_test.c b/isl_test.c
index 485d8b4..f0aee84 100644 (file)
--- a/isl_test.c
+++ b/isl_test.c
@@ -3418,10 +3418,12 @@ static int test_ast(isl_ctx *ctx)
        expr = isl_ast_expr_add(expr1, expr2);
        expr = isl_ast_expr_neg(expr);
        str = isl_ast_expr_to_str(expr);
-       ok = !strcmp(str, "-(A + B)");
+       ok = str ? !strcmp(str, "-(A + B)") : -1;
        free(str);
        isl_ast_expr_free(expr);
 
+       if (ok < 0)
+               return -1;
        if (!ok)
                isl_die(ctx, isl_error_unknown,
                        "isl_ast_expr printed incorrectly", return -1);
@@ -3432,10 +3434,12 @@ static int test_ast(isl_ctx *ctx)
        expr3 = isl_ast_expr_from_id(isl_id_alloc(ctx, "C", NULL));
        expr = isl_ast_expr_sub(expr3, expr);
        str = isl_ast_expr_to_str(expr);
-       ok = !strcmp(str, "C - (A + B)");
+       ok = str ? !strcmp(str, "C - (A + B)") : -1;
        free(str);
        isl_ast_expr_free(expr);
 
+       if (ok < 0)
+               return -1;
        if (!ok)
                isl_die(ctx, isl_error_unknown,
                        "isl_ast_expr printed incorrectly", return -1);