hfinkel accepted this revision. hfinkel added a reviewer: hfinkel. hfinkel added a comment. This revision is now accepted and ready to land.
In http://reviews.llvm.org/D10546#202823, @ahatanak wrote: > In http://reviews.llvm.org/D10546#202675, @hfinkel wrote: > > > I don't think, however, you can ever mark the inline asm call as > > 'readnone', because you have no way of knowing that it does not load > > anything. Any of its inputs could be an address, or used to construct an > > address, to something. The programmer might also know that the address is > > always dereferenceable, and thus won't produce any side effects other than > > its result (and, thus, not mark the statement as volatile). > > > The gcc documentation has the following sentence: > > The "memory" clobber tells the compiler that the assembly code performs > memory reads or writes to items other than those listed in the input and > output operands (for example, accessing the memory pointed to by one of the > input parameters). Okay, sounds good. > I took it to mean that you have to add "memory" to an inline-asm statement's > clobber list in the case it reads from memory using one of the input > registers. If you don't, gcc will treat it as a read-none statement. > > __asm__ ("movl (%1), %0" : "=r" (res) : "r" (ptr) : "memory"); In that case, LGTM. http://reviews.llvm.org/D10546 _______________________________________________ cfe-commits mailing list cfe-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
