Check that APFloat::convert is not trying to target
ppc long double, which doesn't work.

This may break some stuff temporarily, but I want to
avoid the propagation of code that assumes this works.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49983 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp
index 8ecfa35..35de714 100644
--- a/lib/Support/APFloat.cpp
+++ b/lib/Support/APFloat.cpp
@@ -1678,6 +1678,7 @@
   opStatus fs;
 
   assertArithmeticOK(*semantics);
+  assertArithmeticOK(toSemantics);
   lostFraction = lfExactlyZero;
   newPartCount = partCountForBits(toSemantics.precision + 1);
   oldPartCount = partCount();