Hi Christophe,

> -----Original Message-----
> From: Christophe Lyon <[email protected]>
> Sent: Monday, March 4, 2019 13:32
> To: Tamar Christina <[email protected]>
> Cc: James Greenhalgh <[email protected]>; Jakub Jelinek
> <[email protected]>; Kyrill Tkachov <[email protected]>; gcc-
> [email protected]; nd <[email protected]>; Richard Earnshaw
> <[email protected]>; Marcus Shawcroft
> <[email protected]>
> Subject: Re: [PATCH][GCC][AArch64] Have empty HWCAPs string ignored
> during native feature detection
> 
> On Wed, 27 Feb 2019 at 18:32, Tamar Christina <[email protected]>
> wrote:
> >
> > Hi James,
> >
> > > -----Original Message-----
> > > From: James Greenhalgh <[email protected]>
> > > Sent: Wednesday, February 27, 2019 17:22
> > > To: Tamar Christina <[email protected]>
> > > Cc: Jakub Jelinek <[email protected]>; Kyrill Tkachov
> > > <[email protected]>; [email protected]; nd
> > > <[email protected]>; Richard Earnshaw <[email protected]>;
> Marcus
> > > Shawcroft <[email protected]>
> > > Subject: Re: [PATCH][GCC][AArch64] Have empty HWCAPs string ignored
> > > during native feature detection
> > >
> > > On Thu, Feb 07, 2019 at 04:43:24AM -0600, Tamar Christina wrote:
> > > > Hi All,
> > > >
> > > > Since this hasn't been reviewed yet anyway I've updated this patch
> > > > to also
> > > fix the memory leaks etc.
> > > >
> > > > --
> > > >
> > > > This patch makes the feature detection code for AArch64 GCC not
> > > > add features automatically when the feature had no hwcaps string
> > > > to match
> > > against.
> > > >
> > > > This means that -mcpu=native no longer adds feature flags such as
> +profile.
> > > > The behavior wasn't noticed before because at the time +profile
> > > > was added a bug was preventing any feature bits from being added
> > > > by native
> > > detections.
> > > >
> > > > The loop has also been changed as Jakub specified in order to
> > > > avoid a memory leak that was present in the existing code and to
> > > > be slightly more
> > > efficient.
> > > >
> > > > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
> > > >
> > > > Ok for trunk?
> > >
> > > OK. Is this also desirable for a backport?
> >
> > Yes I believe we have this problem in GCC8 as well the profile extensions.
> >
> > Kind regards,
> > Tamar
> >
> 
> Hi Tamar,
> 
> The new test fails with a cross-compiler, because:
> FAIL: gcc.target/aarch64/options_set_10.c (test for excess errors) Excess
> errors:
> cc1: error: unknown value 'native' for -mcpu
> 
> I don't know how to restrict tests to native compilers only.

Ah, thanks, I tested only the elf builds cross. I'll fix it up with a new 
testsuite
directive that checks if -mcpu=native compiles something.

Regards,
Tamar

> 
> Christophe
> 
> > >
> > > Thanks,
> > > James
> > >
> > > >
> > > > Thanks,
> > > > Tamar
> > > >
> > > > gcc/ChangeLog:
> > > >
> > > > 2019-02-07  Tamar Christina  <[email protected]>
> > > >
> > > >     PR target/88530
> > > >     * config/aarch64/aarch64-option-extensions.def: Document it.
> > > >     * config/aarch64/driver-aarch64.c (host_detect_local_cpu):
> > > > Skip
> > > feature
> > > >     if empty hwcaps.
> > > >
> > > > gcc/testsuite/ChangeLog:
> > > >
> > > > 2019-02-07  Tamar Christina  <[email protected]>
> > > >
> > > >     PR target/88530
> > > >     * gcc.target/aarch64/options_set_10.c: New test.
> > > >

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