Re: [PATCH 0/4] jump label patches

[Richard Henderson]

On 10/06/2009 05:14 PM, Roland McGrath wrote:
> Kernel builds usually use -Os.  Is there anything else we can do now (4.4)
> to influence this placement (while keeping the unlikely target block inside
> a scope, i.e. macro, with the asm goto)?

I think -Os includes -freorder-blocks as well.

> 	      if (0) yes: maybe = 1;

Anything with "if (0)" in it (even with __builtin_expect) is going to be 
folded away too early to be useful.

I can't think of any way to manipulate block placement from the source 
level at this time that doesn't add more code along the fast path, 
obviating the asm goto.


r~
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