https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117190
--- Comment #10 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:a6db5908a55adbef0a0dc1eb2a22743064fe17b8 commit r15-4554-ga6db5908a55adbef0a0dc1eb2a22743064fe17b8 Author: Jakub Jelinek <ja...@redhat.com> Date: Tue Oct 22 22:36:03 2024 +0200 c: Better fix for speed up compilation of large char array initializers when not using #embed [PR117190] On Wed, Oct 16, 2024 at 11:09:32PM +0200, Jakub Jelinek wrote: > Apparently my > c: Speed up compilation of large char array initializers when not using #embed > patch broke building glibc. > > The issue is that when using CPP_EMBED, we are guaranteed by the > preprocessor that there is CPP_NUMBER CPP_COMMA before it and > CPP_COMMA CPP_NUMBER after it (or CPP_COMMA CPP_EMBED), so RAW_DATA_CST > never ends up at the end of arrays of unknown length. > Now, the c_parser_initval optimization attempted to preserve that property > rather than changing everything that e.g. inferes array number of elements > from the initializer etc. to deal with RAW_DATA_CST at the end, but > it didn't take into account the possibility that there could be > CPP_COMMA followed by CPP_CLOSE_BRACE (where the CPP_COMMA is redundant). > > As we are peaking already at 4 tokens in that code, peeking more would > require using raw tokens and that seems to be expensive doing it for > every pair of tokens due to vec_free done when we are out of raw tokens. Sorry for rushing the previous patch too much, turns out I was wrong, given that the c_parser_peek_nth_token numbering is 1 based, we can peek also with c_parser_peek_nth_token (parser, 4) and the loop actually peeked just at 3 tokens, not 4. So, I think it is better to revert the previous patch (but keep the new test) and instead peek the 4th non-raw token, which is what the following patch does. Additionally, PR117190 shows one further spot which missed the peek of the token after CPP_COMMA, in case it is incomplete array with exactly 65 elements with redundant comma after it, which this patch handles too. 2024-10-22 Jakub Jelinek <ja...@redhat.com> PR c/117190 gcc/c/ * c-parser.cc (c_parser_initval): Revert 2024-10-17 changes. Instead peek the 4th token and if it is not CPP_NUMBER, handle it like 3rd token CPP_CLOSE_BRACE for orig_len == INT_MAX. Also, check (2 + 2 * i)th raw token for the orig_len == INT_MAX case and punt if it is not CPP_NUMBER. gcc/testsuite/ * c-c++-common/init-5.c: New test.
