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Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
Richard Guenther wrote:
We do that with -fstrict-aliasing, which also changes language semantics.
-fstrict-aliasing is disabled for -O0 and -O1 and enabled for -O[23s].
Yes, and as others have said, this is a bad precedent, and should
not be followed further. Inclusion of -fwrapv would be much worse,
since this has clearly and precisely defined semantics. In the
case of -fno-strict-aliasing, it is more like disabling an
optimization, since as far as I know there is no clear semantic
meaning for this flag (i.e. a meaning that could be expressed
formally at the level of the standard easily).
How do these switches implement your proposal? "All optimiations" sounds
like the -fno-wrapv case we have now.
In a couple of ways:
First it can include semantics other than wrapping
Second, it allows completely unfettered optimization (see
password example), which I think no one would want to do
by default.
Richard.