On Fri, 2011-12-09 at 15:31 -0800, Keith Packard wrote: > On Fri, 09 Dec 2011 11:32:39 -0500, Gaetan Nadon <[email protected]> wrote: > > > The content for CWARNFLAGS will always contain -fno-strict-aliasing. > > I think BASE_CFLAGS should include -fno-strict-aliasing then;
We would be back to square one. It would only be a macro name change. > it retains compatibility with the original C standards on which the X > code is based. The alternative is to have random failures in older code > if people try to switch from CWARNFLAGS to BASE_CFLAGS without > understanding that they would also need to add the -fno-strict-aliasing > option as well. That's a possibility, if they also ignore the aliasing warnings. Note that only 13 drivers use CWARNFLAGS. All others don't have -fno-strict-aliasing. They don't even get the warnings about breaking aliasing rules! > > I'd probably add -fwrapv as well as that preserves the semantics of > integer operations. The GCC idiots seem to think that it's OK to break > existing code to allow them to perform various marginally useful > optimizations... > > /me still remembers spending three days figuring out that -fwrapv was > required to make nickle compile correctly. > Perhaps a different macro for xserver + any other modules deemed to be in need of -fno-strict-aliasing. I don't think we have a definite list of such modules. I'll check back to see if I should drop this patch or not. You may want to look at patch #3 as it uses BASE_CFLAGS as their faith is inter-connected.
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