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Re: [RTL] Canonicalize commutative operations more


On 04/02/2013 04:54 AM, Eric Botcazou wrote:
I wonder if those issues might in most cases be bugs in the back-ends
(optimizations missed depending on the order), that the canonicalization
would make more noticable (and thus easier to fix).

There are certainly such issues in the back-ends (and even ??? comments about
it) so sensible canonicalization is desirable.
Right. The choice between canonicalization and code bloat to support multiple RTL forms computing the same value is a never-ending problem. Where it's clearly made sense we have canonicalized, where it doesn't, we haven't. There's a huge no-mans land in the middle.

Jeff


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