https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88274
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> --- The regression started with r265241 BTW. Here is a reassoc patch I wrote that also fixes this ICE: --- gcc/tree-ssa-reassoc.c.jj 2018-10-23 10:13:25.278875175 +0200 +++ gcc/tree-ssa-reassoc.c 2018-11-30 11:13:37.232393154 +0100 @@ -2537,8 +2537,23 @@ optimize_range_tests_xor (enum tree_code if (!tree_int_cst_equal (lowxor, highxor)) return false; + exp = rangei->exp; + scalar_int_mode mode = as_a <scalar_int_mode> (TYPE_MODE (type)); + int prec = GET_MODE_PRECISION (mode); + if (TYPE_PRECISION (type) < prec + || (wi::to_wide (TYPE_MIN_VALUE (type)) + != wi::min_value (prec, TYPE_SIGN (type))) + || (wi::to_wide (TYPE_MAX_VALUE (type)) + != wi::max_value (prec, TYPE_SIGN (type)))) + { + type = build_nonstandard_integer_type (prec, TYPE_UNSIGNED (type)); + exp = fold_convert (type, exp); + lowxor = fold_convert (type, lowxor); + lowi = fold_convert (type, lowi); + highi = fold_convert (type, highi); + } tem = fold_build1 (BIT_NOT_EXPR, type, lowxor); - exp = fold_build2 (BIT_AND_EXPR, type, rangei->exp, tem); + exp = fold_build2 (BIT_AND_EXPR, type, exp, tem); lowj = fold_build2 (BIT_AND_EXPR, type, lowi, tem); highj = fold_build2 (BIT_AND_EXPR, type, highi, tem); if (update_range_test (rangei, rangej, NULL, 1, opcode, ops, exp, @@ -2581,7 +2596,16 @@ optimize_range_tests_diff (enum tree_cod if (!integer_pow2p (tem1)) return false; - type = unsigned_type_for (type); + scalar_int_mode mode = as_a <scalar_int_mode> (TYPE_MODE (type)); + int prec = GET_MODE_PRECISION (mode); + if (TYPE_PRECISION (type) < prec + || (wi::to_wide (TYPE_MIN_VALUE (type)) + != wi::min_value (prec, TYPE_SIGN (type))) + || (wi::to_wide (TYPE_MAX_VALUE (type)) + != wi::max_value (prec, TYPE_SIGN (type)))) + type = build_nonstandard_integer_type (prec, 1); + else + type = unsigned_type_for (type); tem1 = fold_convert (type, tem1); tem2 = fold_convert (type, tem2); lowi = fold_convert (type, lowi); Do we want that too, or is the exact type in which we compute these uninteresting? Note, unfortunately in this case the enum type has TYPE_PRECISION 32, just TYPE_MAX_VALUE of 15, and we consider such conversions useless, so not really sure how can vrp work reliably with that.