[PATCH] D146466: [clang] diagnose function fallthrough

[Eli Friedman via Phabricator via cfe-commits]

efriedma added a comment.

The problem with a change like that is that it's not clear what the underlying semantic model is.  If we add a flag that says "try to generate code that matches Linux kernel developers' mental model of the underlying machine", or "loop unrolling should try to preserve undefined behavior", or "out-of-bounds memory accesses are well-defined", the semantics are unclear.  The point of having well-defined IR is that a developer can tell whether a transform is legal or not based on reading LangRef, as opposed to trying to blindly guess whether a transform is going to break some user's code.

Making clang generate different IR for specific load/division/etc. operators is much easier to specify; IR has the same meaning it always has, we're just generating IR that's well-defined in more cases.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D146466/new/

https://reviews.llvm.org/D146466