[Bug middle-end/88301] Optimization regression with undefined unsigned overflow
glisse at gcc dot gnu.org
Sat Dec 1 20:25:00 GMT 2018
--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Marc Glisse from comment #2)
> Not sure where this [0, 0] range is coming from...
Well, I guess it is EVRP trying to encode __builtin_unreachable for _3!=0 in
the range information of _3, but not cleaning up (the clean-up happens in
CCP2). But that doesn't quite work because we don't reuse that specific
variable _3, we reuse _2. It used to work because in VRP1 we would replace
_3!=0 with _2!=0.
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