Subject: Re: randconfig build error with next-20150529, in crypto/jitterentropy.c

From: Stephan Mueller <[email-masked]>
Date: Mon, 08 Jun 2015 17:52:49 +0200

Am Monday 08 June 2015, 14:36:30 schrieb Peter Zijlstra:

Hi Peter,
>
>Would something like
>
>#pragma GCC push_options
>#pragma GCC optimize ("-O0")
>static __u64 jent_fold_time(struct rand_data *ec, __u64 time,
>			    __u64 *folded, __u64 loop_cnt)
>{
>	...
>}
>#pragma GCC pop_options
>
>Be an option to allow the file to be compiled with regular optimizations
>enabled?

After doing some tests, I see that neither the min entropy nor the Shannon 
Entropy of the raw noise is affected by using the mentioned pragmas at the 
right locations.

So I will prepare a patch tonight.

Just for my edification: why does an -O0 on a self contained file break the 
compile run? Any why do the pragmas work?

Thanks
Stephan