Re: Why Plan 9 C compilers don't have asm("")

[Richard Henderson]

On Wed, Jul 04, 2001 at 05:22:44PM +0000, Linus Torvalds wrote:
> [ And yes, I know there are optimizing linkers for the alpha around that
>   improve this and notice when they don't need to change GP and can do a
>   straight branch etc.  I don't think GNU ld _still_ does that, but who
>   knows.

GNU ld does it with the "-relax" flag.

>   Even the "good" Digital compilers tended to nop out unnecessary
>   instructions rather than remove them, causing more icache pressure on
>   a CPU that was already famous for needing tons of icache ]

But you're absolutely right about the nopping -- removing the nops would
require debug info and EH info to be re-coded.  The later being a matter
of correctness.  This is a bit nastier than I ever cared to deal with.

r~