On Mon, Mar 5, 2012 at 1:39 PM, Larry Brasfield <larry_brasfi...@iinet.com>wrote:
> On March 5, Richard Hipp wrote: > > On Mon, Mar 5, 2012 at 7:04 AM, Sreekumar TP <sreekumar.tp at gmail.com> >> wrote: >> >> > The crash is a result of -O3 flag used during compiling the library. >> > >> >> A compiler bug, then. OK. Good to know. SQLite has previously uncovered >> bugs in GCC, MSVC, and LLVM. Which compiler are you using? >> > > The fact that an optimization setting alters whether a C program crashes > or not does not imply that there is a compiler bug. Such a result might be > due to a code generation error. Or it might be due to code that is relying > upon undefined behavior, (such as evaluation order, content of struct gaps, > ad infinitum), and the exact (but undefined) behavior changes with > optimization setting. Additionally, pointer aliasing issues, while not > really in the realm of undefined behavior, can occur at higher optimization > levels. While a crash or other bad result that arises from pointer > aliasing might be counted as a compiler bug, it is generally better for > code to not create the opportunity. > Crashes at higher optimizations do not *prove* that the fault is in the compile, but in practice they are pretty good evidence of a compiler bug. The verified compiler bugs found by SQLite in GCC and MSVC occurred only at higher optimization levels. And we do run 100% branch test coverage on the SQLite code using multiple compilers, so one would hope that we have eliminated most cases of undefined behavior by this point. > > Cheers, > -- > Larry Brasfield > > ______________________________**_________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-**bin/mailman/listinfo/sqlite-**users<http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users> > -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
