The Go frontend mishandled unary ^ applied to a signed typed integer constant. In fact it mishandled it so badly that it crashed. This patch fixes the problem. Bootstrapped and ran Go testsuite on x86_64-unknown-linux-gnu. Committed to mainline.
Ian
diff -r b66ddc182445 go/expressions.cc --- a/go/expressions.cc Wed Feb 29 15:41:26 2012 -0800 +++ b/go/expressions.cc Wed Feb 29 16:43:14 2012 -0800 @@ -4300,14 +4300,23 @@ unsigned HOST_WIDE_INT* phwi = new unsigned HOST_WIDE_INT[count]; memset(phwi, 0, count * sizeof(HOST_WIDE_INT)); + size_t obits = utype->integer_type()->bits(); + + if (!utype->integer_type()->is_unsigned() + && mpz_sgn(uval) < 0) + { + mpz_t adj; + mpz_init_set_ui(adj, 1); + mpz_mul_2exp(adj, adj, obits); + mpz_add(uval, uval, adj); + mpz_clear(adj); + } + size_t ecount; mpz_export(phwi, &ecount, -1, sizeof(HOST_WIDE_INT), 0, 0, uval); go_assert(ecount <= count); // Trim down to the number of words required by the type. - size_t obits = utype->integer_type()->bits(); - if (!utype->integer_type()->is_unsigned()) - ++obits; size_t ocount = ((obits + HOST_BITS_PER_WIDE_INT - 1) / HOST_BITS_PER_WIDE_INT); go_assert(ocount <= count); @@ -4322,6 +4331,16 @@ mpz_import(val, ocount, -1, sizeof(HOST_WIDE_INT), 0, 0, phwi); + if (!utype->integer_type()->is_unsigned() + && mpz_tstbit(val, obits - 1)) + { + mpz_t adj; + mpz_init_set_ui(adj, 1); + mpz_mul_2exp(adj, adj, obits); + mpz_sub(val, val, adj); + mpz_clear(adj); + } + delete[] phwi; } return Integer_expression::check_constant(val, utype, location);