https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116347
Christoph Müllner <cmuellner at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2024-10-17 00:00:00 |2024-10-22
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
--- Comment #2 from Christoph Müllner <cmuellner at gcc dot gnu.org> ---
I just noticed that there exists a proposal to address this on the list from
mid August:
https://patchwork.sourceware.org/project/gcc/patch/20240819081442.1955204-1-shiyul...@iscas.ac.cn/
This patch adds the postfix "-series" to tuning identifiers, which are already
used as CPU identifiers (e.g. "thead-c906" -> "thead-c906-series"). Jeff
questioned if CPU core identifiers should be listed (and accepted) as strings
for -mtune. Palmer wrote that he would have a look.
Here's a quick overview of what other backends to with mcpu/mtune:
* aarch64|arm|rs6000/PowerPC: mtune and mcpu flags accept the same identifiers.
mtune selects the tuning struct. mcpu additionally sets the enabled extensions
(similar to march).
* riscv: same as above, but additional identifiers for tuning structs exist
that are accepted for mtune.
* mips: No -mcpu flag. mtune selects the tuning struct.
* x86: mcpu is deprecated and behaves like mtune. mtune sets the tuning struct.
march selects extensions and tuning and accepts the same identifiers as mtune.
I still think that simply suppressing duplicates when generating the help text
would be the solution with the least user impact.
