[cfe-dev] -fmerge-all-constants enabled by default (PR18538)

Chandler Carruth chandlerc at gmail.com
Tue Jan 21 13:51:34 PST 2014

On Tue, Jan 21, 2014 at 1:14 PM, Richard Smith <richard at metafoo.co.uk>wrote:

> Hi!
> The non-conforming optimization -fmerge-all-constants is currently enabled
> by default. That seems surprising, and against our usual approach of trying
> to be correct by default. Is there some code for which this is critically
> important (perhaps without it, the stack usage at -O0 is unacceptable)?
> Can we turn this off by default, or failing that, document very
> prominently that we're not conforming, and explain why? (I'm happy to
> update the documentation if someone can provide a good reason for the
> behavior.)

Back when it was added, there was a reasonably strong arguement that the
standard was wrong and we would like to permit this optimization. Maybe, if
we can resurrect some of these arguments, we can help take a proposal to
the committee?

I think Tanya was actually involved with getting this in originally, but
perhaps my memory is deeply flawed here.
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