> -----Original Message----- > From: Richard Earnshaw <richard.earns...@foss.arm.com> > Sent: Monday, September 5, 2022 2:43 PM > To: Kyrylo Tkachov <kyrylo.tkac...@arm.com>; gcc-patches@gcc.gnu.org > Subject: Re: [PATCH][committed] aarch64: Suggest an -mcpu option when > user passes CPU name to -march > > > > On 05/09/2022 14:35, Kyrylo Tkachov via Gcc-patches wrote: > > Hi all, > > > > This small patch helps users who confuse -march and -mcpu on AArch64. > > Sometimes users pass -march with a CPU name, where they most likely > wanted to > > use -mcpu, which would select the right architecture features *and* tune > for > > their desired CPU. Currently we'll just error out with an unkown > architecture > > message and list the valid architecture options. > > With this patch we check if their string matches a known CPU and suggest > they > > use an -mcpu option instead. > > > > So compiling with -march=neoverse-n1 will now give the error: > > cc1: error: unknown value 'neoverse-n1' for '-march' > > cc1: note: valid arguments are: armv8-a armv8.1-a armv8.2-a armv8.3-a > armv8.4-a armv8.5-a armv8.6-a armv8.7-a armv8.8-a armv8-r armv9-a > > cc1: note: did you mean '-mcpu=neoverse-n1'? > > > > Bootstrapped and tested on aarch64-none-linux-gnu. > > Pushing to trunk. > > Thanks, > > Kyrill > > > > gcc/ChangeLog: > > > > * config/aarch64/aarch64.cc (aarch64_validate_march): Check if > invalid arch > > string is a valid -mcpu string and emit hint. > > > > gcc/testsuite/ChangeLog: > > > > * gcc.target/aarch64/spellcheck_10.c: New test. > > What about the reverse case, passing an architecture to -mcpu?
It'd be good to warn for that too, though I think it's a somewhat less common error. It can be a separate patch in any case. Thanks, Kyrill > > R.
