Messages in this thread | | | Date | Thu, 17 Oct 2013 13:02:15 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH for 3.12] mutex: Avoid gcc version dependent __builtin_constant_p() usage. |
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On Thu, Oct 17, 2013 at 12:54:21PM +0200, Maarten Lankhorst wrote: > op 17-10-13 12:52, Peter Zijlstra schreef: > > On Thu, Oct 17, 2013 at 07:45:29PM +0900, Tetsuo Handa wrote: > >> Commit 040a0a37 "mutex: Add support for wound/wait style locks" used > >> "!__builtin_constant_p(p == NULL)" but gcc 3.x cannot handle such expression > >> correctly, leading to boot failure when built with CONFIG_DEBUG_MUTEXES=y. > > So I completely forgot all about this, but wouldn't something like: > > > > !(__builtin_constant_p(p) && p == NULL) > > > > Not also work and generate the same code? > > > See earlier discussion. It was already answered why that was undesirable. ;)
OK; I forgot if we covered that particular option.. I so hate this patch; but I'm afraid we'll have to take it :-/
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