[APFloat] Set losesInfo on no-op convert

losesInfo would be left unset when no conversion needs to be done.  A
caller such as InstCombine's fitsInFPType would then branch on an
uninitialized value.

Caught using valgrind on an out-of-tree target.

Differential Revision: https://reviews.llvm.org/D46645


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332087 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/APFloat.cpp

@@ -4443,8 +4443,10 @@ APFloat::APFloat(const fltSemantics &Semantics, StringRef S)
 
 APFloat::opStatus APFloat::convert(const fltSemantics &ToSemantics,
                                    roundingMode RM, bool *losesInfo) {
-  if (&getSemantics() == &ToSemantics)
+  if (&getSemantics() == &ToSemantics) {
+    *losesInfo = false;
     return opOK;
+  }
   if (usesLayout<IEEEFloat>(getSemantics()) &&
       usesLayout<IEEEFloat>(ToSemantics))
     return U.IEEE.convert(ToSemantics, RM, losesInfo);