Re: gcc unsigned vs signed compare

[christos%astron.com@localhost (Christos Zoulas)]

In article <20110831202534.GA7800%antioche.eu.org@localhost>,
Manuel Bouyer  <bouyer%antioche.eu.org@localhost> wrote:
>Hello,
>I tracked down a bug on a mips64el platform (see PR 45310), which turns out
>to be a signed vs unsigned compare issue.
>
>In lib/libc/gen/fixunsgen_ieee754.c there is a compare:
>       (exp - mant_dig > sizeof(UINTXX_T)*8-1)
>exp is int, mant_dig is size_t (unsigned long) and sizeof returns size_t.
>gcc generates an unsigned compare for this, which doesn't gives the expected
>result when exp < mant_dig. Is gcc right when generating an unsigned
>compare here ?

Yes, the promotion rule is signed -> unsigned.

christos