https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117847
--- Comment #3 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:0b89341f124eadc689682d01193309225adfec23 commit r15-5887-g0b89341f124eadc689682d01193309225adfec23 Author: Jakub Jelinek <ja...@redhat.com> Date: Tue Dec 3 11:16:37 2024 +0100 bitintlower: Fix up ?ROTATE_EXPR lowering [PR117847] In the ?ROTATE_EXPR lowering I forgot to handle rotation by 0 correctly. INTEGER_CST 0 is very unlikely, it would be probably folded away, but a non-constant count can't use just p - n because then the shift count is out of bounds for zero. In the FE I use n == 0 ? x : (x << n) | (x >> (p - n)) but bitintlower here isn't prepared at this point to have bb split and am not sure if using COND_EXPR is a good idea either, so the patch uses (p - n) % p. Perhaps I should just disable lowering the rotate in the FE for the non-mode precision BITINT_TYPEs too. 2024-12-03 Jakub Jelinek <ja...@redhat.com> PR middle-end/117847 * gimple-lower-bitint.cc (gimple_lower_bitint) <case LROTATE_EXPR>: Use m = (p - n) % p instead of m = p - n for the other shift count. * gcc.dg/torture/bitint-75.c: New test.
