[LLVMdev] The nsw story
David A. Greene
greened at obbligato.org
Tue Dec 6 09:08:38 PST 2011
Eli Friedman <eli.friedman at gmail.com> writes:
>> But since the add nsw returns undef, then isn't c "sext i32 undef to
>> and thus also undef?
> No: it's some value between INT32_MIN and INT32_MAX. Think of undef
> as a read from an arbitrary register: you can't predict what it will
> contain, but you know it contains some representable value.
How does undef not cover the above case? "some value between INT32_MIN
and INT32_MAX" is certainly "some representable value."
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