@@ -122,7+122,7 @@ The Rust abstract machine *does* make a distinction between "relaxed" and "relea
After all, x86 does not have "uninitialized bytes" either, and still our example program above went wrong.
Of course, to explain *why* the abstract machine is defined the way it is, we have to look at optimizations and hardware-level concerns.
After all, x86 does not have "uninitialized bytes" either, and still our example program above went wrong.
Of course, to explain *why* the abstract machine is defined the way it is, we have to look at optimizations and hardware-level concerns.
-But without an abstract machine, it is very hard to ensure that all the optimizations a compiler performs are consistent---in fact, both [LLVM](https://bugs.llvm.org/show_bug.cgi?id=35229) and [GCC](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65752) suffer from miscompilations caused by combining optimizations that all seem fine in isolation, but together cause incorrect code generation.
+But without an abstract machine, it is very hard to ensure that all the optimizations a compiler performs are consistent---in fact, both [LLVM](https://bugs.llvm.org/show_bug.cgi?id=35229) and [GCC](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65752) suffer from miscompilations caused by combining optimizations that all seem [fine in isolation, but together cause incorrect code generation]({% post_url 2020-12-14-provenance %}).
The abstract machine is needed as an ultimate arbiter that determines which optimizations can be safely combined with each other.
I also think that when writing unsafe code, it is much easier to keep in your head a fixed abstract machine as opposed to a set of optimizations that might change any time, and might or might not be applied in any order.
The abstract machine is needed as an ultimate arbiter that determines which optimizations can be safely combined with each other.
I also think that when writing unsafe code, it is much easier to keep in your head a fixed abstract machine as opposed to a set of optimizations that might change any time, and might or might not be applied in any order.