[PATCH] D28404: IRGen: Add optnone attribute on function during O0

Mehdi AMINI via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Tue Jan 10 11:11:47 PST 2017

mehdi_amini added a comment.

In https://reviews.llvm.org/D28404#641538, @probinson wrote:

> > - optnone isn't *really* no optimizations: clearly this is true, but then neither is -O0. We run the always inliner, a couple of other passes, and we run several parts of the code generators optimizer. I understand why optnone deficiencies (ie, too many optimizations) might be frustrating, but having *more users* seems likely to make this *better*.
> We have picked all the low-hanging fruit there, and probably some medium-hanging fruit.  Mehdi did have the misunderstanding that optnone == -O0 and that I think was worth correcting.

As I stand right now, there hasn't been any correction. 
I still consider the fact that `optnone` wouldn't produce the "same" result (modulo corner cases around `merging global variables` for instance) as O0 a bug that need to be fixed.

(Disabling passes for compile time at O0 stays I compile time improvement, I never suggested to stop doing this...)


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