[LLVMdev] [MC] Removing relaxation control

[Joerg Sonnenberger]

On Sat, Feb 26, 2011 at 11:51:48AM -0800, Chris Lattner wrote:
> That looks like a 1.5% speedup in realtime and 10% speedup in system
> time (though I'm not sure I believe that).  I think it should stay on
> for -O0 for C files.  Turning it off at -O0 for .s files makes perfect
> sense to me though.

I was looking into this and there is a problem with -save-temps.
The attached patch works and does the right thing, if that option is not
used. With -save-temps, the problem is that at that point, it is
impossible to distingiush between C input and (preprocessed) assembler
files. For the former, POLA would dictate that -mrelax-all is used for
-O0, for the latter it is definitely not desirable. I can't find a clean
way to do without making a mess of the action construction.

Joerg
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