https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111817
--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <[email protected]>: https://gcc.gnu.org/g:35476a0da65fb13651238e38ae98398c78f12b2e commit r16-6588-g35476a0da65fb13651238e38ae98398c78f12b2e Author: Jakub Jelinek <[email protected]> Date: Thu Jan 8 23:05:58 2026 +0100 stmt: Fix up parse_input_constraint [PR111817] The following invalid testcase ICEs, because we: 1) for some strange reason ignore invalid punctuations in parse_output_constraint, which has just default: if (!ISALPHA (*p)) break; compared to parse_input_constraint default: if (! ISALPHA (constraint[j])) { error ("invalid punctuation %qc in constraint", constraint[j]); return false; } Haven't touched this because I fear it could break real-world code 2) the checking whether = or + is first in the output constraint is a warning only: if (p != constraint) warning (0, "output constraint %qc for operand %d " "is not at the beginning", *p, operand_num); 3) parse_input_constraint parses also the corresponding output constraint if the input constraint has a number as the only variant, but even the comment removed in the following patch explains that it doesn't work correctly and skips the first character; now, usually that is not a big deal because if the first character of the output constraint is = or + as it should, then the checking doesn't do anything; but as 2) is just a warning, we accept it and then we fail to check it 4) far later on we parse the whole output constraint when input constraint refers to it and assert it succeeds, which it doesn't due to 1), 2) and 3) The following patch fixes the 3) spot, when switching to the output constraint, instead of setting j = 0; and break; (== continue;) so that it first does j += CONSTRAINT_LEN (constraint[0], constraint+0) and thus usually starts at second, sometimes third character of the output constraint it uses goto before the loop which sets j = 0; and doesn't do the j += ... 2026-01-08 Jakub Jelinek <[email protected]> PR middle-end/111817 * stmt.cc (parse_input_constraint): For matching construct, goto before the loop without changing j instead of break. Remove comment about that problem. * c-c++-common/pr111817.c: New test.
