https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84873
--- Comment #7 from rguenther at suse dot de <rguenther at suse dot de> --- On Thu, 15 Mar 2018, jakub at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84873 > > --- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> --- > Why the > + if (TREE_CODE (*op1_p) == INTEGER_CST) > + *op1_p = fold_convert (unsigned_type_node, *op1_p); > + else > + *op1_p = build1 (NOP_EXPR, unsigned_type_node, *op1_p); > ? Just change the convert to fold_convert... I hope the FE ensures that the > shift count has a sane type (some integral one). Because it's fold_binary_op_with_conditional_arg which introduces the tree sharing. So if, say, *op1_p was (long) (x == 0) + (long) y then fold_convert will fold away the conversion and re-fold the PLUS which then may reach fold_binary_op_with_conditional_arg again. I might have used tree tem = fold_unary_to_constant (...); if (!tem) tem = build1 (...); *op1_p = tem; but fold_unary_to_constant uses TREE_CONSTANT as well ... (but it looks like COND_EXPR will never be TREE_CONSTANT at least).
