Re: [PATCH] RISC-V: Update multilib-generator to handle V

[Palmer Dabbelt <palmer@rivosinc.com>]

On Tue, 18 Apr 2023 08:44:24 PDT (-0700), gcc-patches@gcc.gnu.org wrote:
>> Yep, if I drop the non-canonicial strings via
>>
>>     diff --git a/gcc/config/riscv/multilib-generator b/gcc/config/riscv/multilib-generator
>>     index 58b7198b243..a63a4d69c18 100755
>>     --- a/gcc/config/riscv/multilib-generator
>>     +++ b/gcc/config/riscv/multilib-generator
>>     @@ -174,7 +174,7 @@ for cmodel in cmodels:
>>          ext_combs = expand_combination(ext)
>>          alts = sum([[x] + [x + y for y in ext_combs] for x in [arch] + extra], [])
>>          alts = filter(lambda x: len(x) != 0, alts)
>>     -    alts = alts + list(map(lambda a : arch_canonicalize(a, args.misa_spec), alts))
>>     +    alts = list(map(lambda a : arch_canonicalize(a, args.misa_spec), alts))
>>
>>          # Drop duplicated entry.
>>          alts = unique(alts)
>>
>> then I can't link `-march=rv32imafdcv`, I need
>> `-march=rv32imacv_zicsr_zve32f_zve32x_zve64x_zvl128b_zvl32b_zvl64b`.  That's
>> kind of a headache for users to type in.
>
> Yes, that's a headache for users, but arch string canonicalization is
> hiddened at the process,
> so the user could still just use rv32imafdcv at compile time and
> multi-lib config.
>
> And the driver and multilib-generator (with arch_canonicalize) script
> will handle those headache in the background.

Sorry, I'm not exactly sure what you're trying to say.  I just rebuilt 
GCC with this patch (and t-linux-multilib regenerated from it), it's not 
resolving multlibs for the short names.