Reduce branching on empty matrix elements as well.

This makes a big difference in performance.

Change-Id: I88b48d10ff575d80c1c139278dc207d921f15848

sc/inc/compare.hxx

@@ -70,6 +70,11 @@ double CompareFunc( double fCell1, const Compare::Cell& rCell2, CompareOptions*
 double CompareFunc( const Compare::Cell& rCell1, double fCell2, CompareOptions* pOptions = NULL );
 double CompareFunc( double fCell1, double fCell2 );
 
+/**
+ * Left cell is empty while the right cell is numeric.
+ */
+double CompareEmptyToNumericFunc( double fCell2 );
+
 }
 
 #endif

sc/source/core/tool/compare.cxx

@@ -357,6 +357,26 @@ double CompareFunc( double fCell1, double fCell2 )
     return fRes;
 }
 
+double CompareEmptyToNumericFunc( double fCell2 )
+{
+    // Keep DoubleError if encountered
+    // #i40539# if bEmpty is set, bVal/nVal are uninitialized
+    if (!rtl::math::isFinite(fCell2))
+        return fCell2;
+
+    double fRes = 0;
+    if (fCell2 != 0.0)
+    {
+        if (fCell2 < 0.0)
+            fRes = 1;       // empty cell > -x
+        else
+            fRes = -1;      // empty cell < x
+    }
+    // else: empty cell == 0.0
+
+    return fRes;
+}
+
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

sc/source/core/tool/scmatrix.cxx

@@ -1359,6 +1359,13 @@ class CompareMatrixToNumericFunc : std::unary_function<MatrixImplType::element_b
         maResValues.push_back(evaluate(fVal, mrComp.meOp));
     }
 
+    void compareLeftEmpty( size_t nSize )
+    {
+        double fVal = sc::CompareEmptyToNumericFunc(mfRightValue);
+        bool bRes = evaluate(fVal, mrComp.meOp);
+        maResValues.resize(maResValues.size() + nSize, bRes);
+    }
+
 public:
     CompareMatrixToNumericFunc( size_t nResSize, sc::Compare& rComp, double fRightValue, sc::CompareOptions* pOptions ) :
         mrComp(rComp), mfRightValue(fRightValue), mpOptions(pOptions)
@@ -1409,13 +1416,8 @@ public:
             }
             break;
             case mdds::mtm::element_empty:
-            {
-                rCell.mbValue = false;
-                rCell.mbEmpty = true;
-                rCell.maStr = svl::SharedString::getEmptyString();
-                for (size_t i = 0; i < node.size; ++i)
-                    compare();
-            }
+                compareLeftEmpty(node.size);
+            break;
             default:
                 ;
         }
@@ -1627,7 +1629,9 @@ ScMatrixRef ScMatrixImpl::CompareMatrix(
     {
         if (rComp.maCells[1].mbValue && !rComp.maCells[1].mbEmpty)
         {
-            // Matrix on the left, and a numeric value on the right.
+            // Matrix on the left, and a numeric value on the right.  Use a
+            // function object that has much less branching for much better
+            // performance.
             CompareMatrixToNumericFunc aFunc(nSize, rComp, rComp.maCells[1].mfValue, pOptions);
             maMat.walk(aFunc);