Re: [patch 02/2] allow gcc4 to optimize unit-at-a-time

[Andi Kleen]

Ingo Molnar <mingo@xxxxxxx> writes:

> allow gcc4 compilers to optimize unit-at-a-time - which results in gcc
> having a wider scope when optimizing. This also results in smaller code
> when optimizing for size. (gcc4 does not have the stack footprint
> problem of gcc3 compilers.)

I never had any trouble with stack footprint even with gcc 3.3 on x86-64
and unit-at-a-time and it was always enabled. 

But one caveat: turning on unit-at-a-time makes objdump -S / make
foo/bar.lst with CONFIG_DEBUG_INFO essentially useless because objdump
cannot deal with functions being out of order in the object file. This
can be a big problem while analyzing oopses - essentially you have
to analyze the functions without source level information. And with
unit-at-a-time they become bigger so it's more difficult.

But I still think it's a good idea.

-Andi
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