On 1/9/2026 8:10 AM, Robin Dapp wrote:
Hi,
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.
Bootstrapped and regtested on x86, power10, aarch64 still running.
Regtested on riscv64.
Regards
Robin
PR rtl-optimization/123501
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.
OK. Thanks for chasing this down.
jeff
