Re: P.S. Follow up to my last post

[jacob navia <jacob@jacob.remcomp.fr>]

OK, there is no bug, I didn’t expect anything else.

SO:

To use all the instruction of the processor he/she is running on, the user should:

1)Be aware that gcc doesn’t see crucial instructions of the processor by verifying its assembler output.

2) Be aware that there is an (undocumented) option -march… that will enable the assembler and the compiler to generate all the instructions of the current processor.

Well, there is NO BUG!

This is by design then.

Thank you very much.

Jacob



> Le 25 août 2023 à 14:00, Jan Beulich <jbeulich@suse.com> a écrit :
> 
> On 25.08.2023 13:52, jacob navia wrote:
>> The lack of the Ebb instructions is CRUCIAL for performance when accessing tables / arrays!
>> This instructions allow to combine an addition and a shift by 1, 2 or 3, to access tables of shorts, ints or doubles.
>> This speeds up the access to tables enormously and would allow gcc to generate much better code.
> 
> Since you're writing to binutils@, you may want to also mention what gas
> bug you think you see. So far (also in the other mail) you've talked of
> only gcc. If you meant to say that like in gcc you need to enable use of
> the instructions in gas, then yes, that's the way the RISC-V assembler
> works (like e.g. also the PPC one, but unlike e.g. the x86 one).
> 
> Jan