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From: "simon.willcocks at gmx dot de" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug inline-asm/101422] register variable uninitialised before
 passing to asm
Date: Sun, 11 Jul 2021 19:13:44 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101422

--- Comment #5 from Simon Willcocks <simon.willcocks at gmx dot de> ---
(In reply to Andrew Pinski from comment #4)
> (In reply to Simon Willcocks from comment #2)
> > That's not an accurate description of the problem; the value of the var=
iable
> > is being passed, not its address. As a register variable, it doesn't ha=
ve an
> > address.
>=20
> It is the address of the array that is being passed (I was copying and
> pasting from another bug).
> register uint32_t *cap_and_join asm( "r5" ) =3D cap_and_join_style;
> Is the same as:
> register uint32_t *cap_and_join asm( "r5" ) =3D &cap_and_join_style[0];
>=20
> Because array decays to pointers :).

I know. I've been doing this for a while, now. *That* register variable and=
 the
array it pointed to were correctly initialised. r0-r3 are clobbered by any
function call, although I didn't program a function call, the compiler did.=