Re: [PATCH] RISC-V: Use vclmul for CRC expansion if available

[Jeff Law]

On 5/4/25 10:49 PM, Anton Blanchard wrote:

If the vector version of clmul (vclmul) is available and the scalar
one is not, use it for CRC expansion.

gcc/Changelog:

        * config/riscv/bitmanip.md (crc_rev<ANYI1:mode><ANYI:mode>4): Check
        TARGET_ZVBC.
        (crc<SUBX1:mode><SUBX:mode>4): Likewise.
        * config/riscv/riscv.cc (expand_crc_using_clmul): Emit code using
        vclmul if TARGET_ZVBC.
        (expand_reversed_crc_using_clmul): Likewise.

gcc/testsuite/ChangeLog:

        * gcc.target/riscv/rvv/base/crc-builtin-zvbc.c: New test.

So this failed pre-commit CI:

https://github.com/ewlu/gcc-precommit-ci/issues/3301#issuecomment-2849962485

Whatever failure that is needs to be fixed :-)


Jeff