[PATCH] D46648: [SimplifyLibcalls] Optimize string concats using s(n)printf

[Dávid Bolvanský via Phabricator via llvm-commits]

xbolva00 added a comment.

In https://reviews.llvm.org/D46648#1093273, @efriedma wrote:

> Yes, we can do anything if we prove the code has undefined behavior, but I'm not sure why we would prefer a call to strncat over "unreachable".


"unreachable" is emitted when? 
snprintf(buf, n, "%s%s", buf, str)  works normally, I see no "unreachable".


Repository:
  rL LLVM

https://reviews.llvm.org/D46648