Re: [PATCH] arm64/io: Don't use WZR in writel
From: Marc Gonzalez
Date: Mon Mar 18 2019 - 13:30:30 EST
On 18/03/2019 18:19, Robin Murphy wrote:
> For the context bank reset, yes, I am assuming that no complier will
> ever be perverse enough to detect that cfg is not written after the
> NULL check and immediately reallocate it to XZR for no good reason.
> I'd like to think that assumption is going to hold for the reasonable
> scope of this particular workaround, though.
I'm not sure I understand the above paragraph.
In code such as:
if (val == 0) foo(val);
gcc's algorithm is likely to figure out that the code is equivalent to
if (val == 0) foo(0)
and perform constant-propagation, etc.
Is that what we're talking about?