From: Arnd Bergmann
> Sent: 20 April 2021 22:20
>
> On Tue, Apr 20, 2021 at 11:14 PM Vineet Gupta
> <Vineet.Gupta1@xxxxxxxxxxxx> wrote:
> > On 4/20/21 12:07 AM, Arnd Bergmann wrote:
>
> > >
> > > which means that half the 32-bit architectures do this. This may
> > > cause more problems when arc and/or microblaze want to support
> > > 64-bit kernels and compat mode in the future on their latest hardware,
> > > as that means duplicating the x86 specific hacks we have for compat.
> > >
> > > What is alignof(u64) on 64-bit arc?
> >
> > $ echo 'int a = __alignof__(long long);' | arc64-linux-gnu-gcc -xc -
> > -Wall -S -o - | grep -A1 a: | tail -n 1 | cut -f 3
> > 8
>
> Ok, good.
That test doesn't prove anything.
Try running on x86:
$ echo 'int a = __alignof__(long long);' | gcc -xc - -Wall -S -o - -m32
.file ""
.globl a
.data
.align 4
.type a, @object
.size a, 4
a:
.long 8
.ident "GCC: (Ubuntu 5.4.0-6ubuntu1~16.04.10) 5.4.0 20160609"
.section .note.GNU-stack,"",@progbits
Using '__alignof__(struct {long long x;})' does give the expected 4.
__alignof__() returns the preferred alignment, not the enforced
alignmnet - go figure.
David
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