Kris Jurka <[EMAIL PROTECTED]> writes: > Gcc 4.3 has started to perform optimizations based on the denial of the > existence of signed overflow. > ... > I don't understand the difference between -fwrapv and > -fno-strict-aliasing, but it seems we need at least one of them.
I don't see -fno-strict-overflow listed at all in the manual for gcc 4.1. So I think we should go for -fwrapv, which is defined thus: `-fwrapv' This option instructs the compiler to assume that signed arithmetic overflow of addition, subtraction and multiplication wraps around using twos-complement representation. This flag enables some optimizations and disables others. This option is enabled by default for the Java front-end, as required by the Java language specification. and so doesn't sound nearly as bad as Jakub painted it ;-). If we use the other, we are assuming that there are no problems in 4.1, which feels to me like a dangerous assumption. 4.1 *did* break mysql, remember; and we have no regression tests checking most of these security-related overflow tests, so we have no direct proof that we are not broken. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers