https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121663
--- Comment #6 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:5440f4ceee3152148c6c212f57b85da918b66abf commit r16-3509-g5440f4ceee3152148c6c212f57b85da918b66abf Author: Jakub Jelinek <[email protected]> Date: Tue Sep 2 12:18:52 2025 +0200 tree-cfg: Fix up assign_discriminator ICE with too large #line [PR121663] As mentioned in the PR, LOCATION_LINE is represented in an int, and while we have -pedantic diagnostics (and -pedantic-error error) for too large #line, we can still overflow into negative line numbers up to -2 and -1. We could overflow to that even with valid source if it says has #line 2147483640 and then just has 2G+ lines after it. Now, the ICE is because assign_discriminator{,s} uses a hash_map with int_hash <int64_t, -1, -2>, so values -2 and -1 are reserved for deleted and empty entries. We just need to make sure those aren't valid. One possible fix would be just that - discrim_entry &e = map.get_or_insert (LOCATION_LINE (loc), &existed); + discrim_entry &e + = map.get_or_insert ((unsigned) LOCATION_LINE (loc), &existed); by adding unsigned cast when the key is signed 64-bit, it will never be -1 or -2. But I think that is wasteful, discrim_entry is a struct with 2 unsigned non-static data members, so for lines which can only be 0 to 0xffffffff (sure, with wrap-around), I think just using a hash_map with 96bit elts is better than 128bit. So, the following patch just doesn't assign any discriminators for lines -1U and -2U, I think that is fine, normal programs never do that. Another possibility would be to handle lines -1U and -2U as if it was say -3U. 2025-09-02 Jakub Jelinek <[email protected]> PR middle-end/121663 * tree-cfg.cc (assign_discriminator): Change map argument type from hash_map with int_hash <int64_t, -1, -2> to one with int_hash <unsigned, -1U, -2U>. Cast LOCATION_LINE to unsigned. Return early for (unsigned) LOCATION_LINE above -3U. (assign_discriminators): Change map type from hash_map with int_hash <int64_t, -1, -2> to one with int_hash <unsigned, -1U, -2U>. * gcc.dg/pr121663.c: New test.
