[PATCH] D19300: delete the llvm.expect intrinsic and its lowering pass

[Sanjay Patel via llvm-commits]

spatel added inline comments.

================
Comment at: lib/IR/AutoUpgrade.cpp:664
@@ +663,3 @@
+      // The expect intrinsic always lowered to its first argument.
+      // TODO: We could create the appropriate metadata here to better support
+      // legacy code?
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davidxl wrote:
> Is there a reason not to upgrade it properly with meta data?
> 
> Another question for deprecation, can you just remove the documentation and leave the support for the intrinsic support for now?
AFAIK, we don't make any guarantees to support legacy IR, except that we don't die processing it or miscompile it, so this is the minimal patch. Given that we're still losing metadata and/or not using it in a lot of cases (PR27344), I figured we should just focus on improving that instead of spending time on backwards support. If others disagree, I can add it.

If we just remove the docs, we'd still be doing unnecessary work for every compile, right? I don't see any reason to take that path.




http://reviews.llvm.org/D19300