[llvm] r332087 - [APFloat] Set losesInfo on no-op convert

[Sven van Haastregt via llvm-commits]

Author: svenvh
Date: Fri May 11 02:45:42 2018
New Revision: 332087

URL: http://llvm.org/viewvc/llvm-project?rev=332087&view=rev
Log:
[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

Modified:
    llvm/trunk/lib/Support/APFloat.cpp

Modified: llvm/trunk/lib/Support/APFloat.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/APFloat.cpp?rev=332087&r1=332086&r2=332087&view=diff
==============================================================================
--- llvm/trunk/lib/Support/APFloat.cpp (original)
+++ llvm/trunk/lib/Support/APFloat.cpp Fri May 11 02:45:42 2018
@@ -4443,8 +4443,10 @@ APFloat::APFloat(const fltSemantics &Sem
 
 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);