On Jul 5, 2008, at 5:32 PM, Wolfgang Denk wrote: > In message <[EMAIL PROTECTED]> > you wrote: >> When we building with gcc-4.3.x on a ppc host we get the following >> warnings: >> >> dlmalloc.c: In function 'malloc_extend_top': >> dlmalloc.c:1971: warning: dereferencing type-punned pointer will >> break strict-aliasing rules >> dlmalloc.c:1999: warning: dereferencing type-punned pointer will >> break strict-aliasing rules > ... >> This is due to pointer aliasing that the dlmalloc code does and >> depends on. > > Can you please explain why the dlmalloc code depends on this?
That's what Scott said when I asked about this on the list. > In my experience so far it has always been possible to avoid such > warnings by trivial changes to the code (the tricky part was usually > to understand what the exact problem was and what changes were > necessary). > >> Instead of trying trying to work around the warnings, we use the >> per file >> CFLAGs to disable the warnings via -fno-strict-aliasing. > > I tend to reject this patch. I would much rather have the problem > fixed in the sources. Hushing up compiler warnings has never been a > good idea. I'm all for trying to fix the code to git rid of the warnings, however nothing I tried was able to accomplish that. The root of the warnings is the bin_at() macro: #define bin_at(i) ((mbinptr)((char*)&(av_[2*(i) + 2]) - 2*SIZE_SZ)) #define next_bin(b) ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr))) #define prev_bin(b) ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr))) - k ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ U-Boot-Users mailing list U-Boot-Users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/u-boot-users
