[PATCH] D26872: Outliner: Add MIR-level outlining pass

[Sean Silva via Phabricator via llvm-commits]

silvas added a comment.

In https://reviews.llvm.org/D26872#686220, @MatzeB wrote:

> ?!? This should be true for most compiler transformations. I don't know how these problems are handled in practice but I doubt they enable compiler optimizations. I don't see why we should start this discussion with this particular review.


I agree that we don't want to discuss it in this review (that's why I said "down the road"), but most compiler transformations I can think of remove indirection or otherwise simplify things towards the set of "constant time" instructions (such as elementary reg-reg adds and such). This pass introduces call instructions into arbitrary code (and calls on x86 architecturally write to memory and are subject to branch prediction, etc.). I agree, let's not have this discussion here though.


https://reviews.llvm.org/D26872