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Re: [RFC] Isolate & simplify paths with undefined behaviour

On 10/18/13 15:15, Marc Glisse wrote:

On Fri, 18 Oct 2013, Jeff Law wrote:


On 10/18/13 14:31, Marc Glisse wrote:


But once you have that pointer defined by a PHI containing a zero, you
look at all its uses, trying to find one that proves the pointer is
non-zero

What are you going to do with that information?


Uh? I must have been very unclear in my post, this sentence was supposed
to describe what *your* patch is doing...

Ah, no worries.  Sometimes email is a lousy medium for communication.


Yes, precisely. All I was talking about was separating the predicate:
"this statement results in UB if that SSA_NAME pointer is NULL" into its
own function, and we happen to already have a function in VRP which does
that.
Yes, good point. Sharing that routine would be advisable for various reasons. I don't offhand see anything VRP specific in there, so it ought to be relatively easy. 


Jeff
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