Re: [CRYPTO]: Miscompiling sha256.c by gcc 3.2.3 and arch pentium3,4

From: Jakub Jelinek
Date: Fri Jan 30 2004 - 14:51:47 EST


On Fri, Jan 30, 2004 at 11:14:07AM -0600, Andy Isaacson wrote:
> On Fri, Jan 30, 2004 at 11:35:20AM -0500, James Morris wrote:
> > - const u8 padding[64] = { 0x80, };
> > + static u8 padding[64] = { 0x80, };
>
> The RedHat bug suggests 'static const' as the appropriate replacement.
>
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=114610#c4
>
> Unfortunately that probably means an extra 64 bytes of text, rather than
> the 10 or so bytes of instructions to do the memset and store. Ideally
> padding[] would be allocated in BSS rather than text or the stack (and
> initialized with { 0x80, } at runtime), but I guess you can't have
> everything.

Or you can use
u8 padding[64] = { 0x80 };
if you really want to initialize it at runtime and want to work around the
compiler bug. It shouldn't be any less efficient than
const u8 padding[64] = { 0x80 };
since it is used just once, passed to non-inlined function.

Jakub
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