From 5ad5c3c7ed231d9c319cbe91f74f88f8bce59688 Mon Sep 17 00:00:00 2001
From: Sven van Haastregt <sven.vanhaastregt@arm.com>
Date: Fri, 11 May 2018 09:45:42 +0000
Subject: [PATCH] [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

llvm-svn: 332087
---
 llvm/lib/Support/APFloat.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Support/APFloat.cpp b/llvm/lib/Support/APFloat.cpp
index 9035017a9c48..24005c1890c9 100644
--- a/llvm/lib/Support/APFloat.cpp
+++ b/llvm/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);