[Libreoffice-commits] core.git: 2 commits - sc/inc sc/source

[Eike Rathke]

 sc/inc/math.hxx                  |   29 +++++++++++++++++++++++++++++
 sc/source/core/tool/interpr3.cxx |    2 +-
 2 files changed, 30 insertions(+), 1 deletion(-)

New commits:
commit 8747442d179367a9cea652643a516021fa7c5510
Author: Eike Rathke <erack at redhat.com>
Date:   Thu Aug 13 22:36:20 2015 +0200

    use sc::divide() for -fsanitize=float-divide-by-zero triggered by unit test
    
    Change-Id: I370f2f5e3e0ceb40051cbf2f806072f4fd213811

diff --git a/sc/source/core/tool/interpr3.cxx b/sc/source/core/tool/interpr3.cxx
index ce3dc91..3fad7e7 100644
--- a/sc/source/core/tool/interpr3.cxx
+++ b/sc/source/core/tool/interpr3.cxx
@@ -2850,7 +2850,7 @@ void ScInterpreter::ScChiTest()
             {
                 double fValX = pMat1->GetDouble(i,j);
                 double fValE = pMat2->GetDouble(i,j);
-                fChi += (fValX - fValE) * (fValX - fValE) / fValE;
+                fChi += sc::divide( (fValX - fValE) * (fValX - fValE), fValE);
             }
             else
             {
commit d0d76a9aad90c8f07330da7f67eef5c607a27aec
Author: Eike Rathke <erack at redhat.com>
Date:   Thu Aug 13 22:03:53 2015 +0200

    add sc::divide() for defined -fsanitize=float-divide-by-zero behavior
    
    Change-Id: I3af85344119ca0056a127a5278e8993f9d79e2f9

diff --git a/sc/inc/math.hxx b/sc/inc/math.hxx
index 8a95f21..46f9a1d 100644
--- a/sc/inc/math.hxx
+++ b/sc/inc/math.hxx
@@ -24,12 +24,41 @@
 
 namespace sc {
 
+/** Return fNumerator/fDenominator if fDenominator!=0 else #DIV/0! error coded
+    into double.
+ */
 inline double div( const double& fNumerator, const double& fDenominator )
 {
     return (fDenominator != 0.0) ? (fNumerator / fDenominator) :
         CreateDoubleError( errDivisionByZero);
 }
 
+/** Return fNumerator/fDenominator if fDenominator!=0 else +-Infinity if
+    fNumerator!=0 or NaN if fNumerator==0.
+
+    This allows to build/run with -fsanitize=float-divide-by-zero and have a
+    defined behavior for the otherwise undefined division by zero case ("If the
+    second operand of / or % is zero the behavior is undefined."
+    ([expr.mul]/4)).
+
+    The Calc interpreter gracefully handles Infinity or NaN double values
+    encountered as interim or final results, using this function we can ensure
+    defined behavior where desired.
+
+    Use where the double coded error creating div() is not wanted.
+ */
+inline double divide( const double& fNumerator, const double& fDenominator )
+{
+    if (fDenominator == 0.0) {
+        if (std::isfinite(fNumerator) && fNumerator != 0.0) {
+            return std::copysign(INFINITY, fNumerator);
+        } else {
+            return NAN;
+        }
+    }
+    return fNumerator / fDenominator;
+}
+
 }
 
 #endif