assert(0) -> LLVM_UNREACHABLE.
Make llvm_unreachable take an optional string, thus moving the cerr<< out of
line.
LLVM_UNREACHABLE is now a simple wrapper that makes the message go away for
NDEBUG builds.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75379 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/ErrorHandling.cpp b/lib/Support/ErrorHandling.cpp
index 2a5d906..f2e247c 100644
--- a/lib/Support/ErrorHandling.cpp
+++ b/lib/Support/ErrorHandling.cpp
@@ -44,7 +44,9 @@
   exit(1);
 }
 
-void llvm_unreachable(void) {
+void llvm_unreachable(const char *msg) {
+  if (msg)
+    errs() << msg << "\n";
   abort();
 }
 }