If the power of 5 is exact, and the reciprocal exact, the error is zero not one half-ulps. This prevents an infinite loop in rare cases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42950 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp
index 65ec785725..a4c1affb7a 100644
--- a/lib/Support/APFloat.cpp
+++ b/lib/Support/APFloat.cpp
@@ -1947,7 +1947,7 @@ APFloat::roundSignificandWithExponent(const integerPart *decSigParts,
           excessPrecision = calcSemantics.precision;
       }
       /* Extra half-ulp lost in reciprocal of exponent.  */
-      powHUerr = 1 + powStatus != opOK;
+      powHUerr = (powStatus == opOK && calcLostFraction == lfExactlyZero) ? 0: 2;
     }
 
     /* Both multiplySignificand and divideSignificand return the