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Re: [PATCH] Check -fwrapv before simplifying A - B < 0 to A < B


Bonzini wrote:
	* simplify-rtx.c (simplify_relational_operation): If
	flag_wrapv is set, do not move terms between the two
	side of a relational operator.

OK.


I would very much prefer to see some justification for every patch, even if you think it is fairly obvious. I am much more confident about a patch approval if I know it fixes a real problem with a real testcase. This also helps if we discover an obscure problem with this change 5 years from now. We won't have any record of why the change was made, which could make further changes difficult.

What I find convincing about this is that there are only a handful of other places that use flag_wrapv, and several of them are disabling similar optimizations in fold-const.c.
--
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com



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