https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123501
--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Robin Dapp <[email protected]>: https://gcc.gnu.org/g:659f4d0e1e9a740fa8a18636bd7ec91cfefee26c commit r16-6740-g659f4d0e1e9a740fa8a18636bd7ec91cfefee26c Author: Robin Dapp <[email protected]> Date: Fri Jan 9 13:25:40 2026 +0100 rtlanal: Determine nonzero bits of popcount from operand [PR123501]. The PR involves large mask vectors (e.g. V128BI) from which we take the popcount. Currently a (popcount:DI (V128BI)) is assumed to have at most 8 set bits as we assume the popcount operand also has DImode. This patch uses the operand mode for unary operations and thus calculates a proper nonzero-bits mask. We could do the same estimate for ctz and clz but they use nonzero in a non-poly way and I didn't want to change more than necessary. Therefore the patch just returns -1 when we have a different operand mode for ctz/clz. PR rtl-optimization/123501 PR rtl-optimization/123444 gcc/ChangeLog: * rtlanal.cc (nonzero_bits1): Use operand mode instead of operation mode. gcc/testsuite/ChangeLog: * gcc.target/riscv/rvv/autovec/reduc/pr123501.c: New test.
