Handle zero or empty cells properly when using OpenCL for division

This is a combination of 4 commits from master:

4f4daf163e92d113b62cc19fb0b7f5ec05dce48a: Introduce SetResultError()

f7c6089c0f5ac7976149d270f6d9694ef8ed7cfd: Be prepared to handle error codes
encoded in NaNs ("double error")

f6dfb3b4098f4554782e35fdb471ef69f2f53386: Create proper error when dividing by
zero. Create a so-called "double error", i.e. a NaN with a error code payload.

f5e7207053b857b6903a0ab9c161bed9ad7bcee9: Handle zero and empty cells (which
also means zero) in OpenCL for division.

Not sure if it makes sense to keep having OpDiv a subclass of Reduction.
There is no DIV() function that would take a range of cells, so it isn't
really comparable to the other Reducion subclasses. But let's keep hat as it
is for now.

We need to handle three cases specially in the OpenCL: Dividing by an empty
cell which should produce an #DIV/0! error, dividing an empty cell by zero
which also should produce #DIV/0!, and dividing an empty cell with anything
else number which should produce 0.

Change-Id: I86d86f652047d6f9e3c095c3ef135a8f5396b000
Reviewed-on: https://gerrit.libreoffice.org/14395
Reviewed-by: Jan Holesovsky <kendy@collabora.com>
Tested-by: Jan Holesovsky <kendy@collabora.com>

2 files changed, 69 insertions, 10 deletions

diff --git a/sc/source/core/opencl/formulagroupcl.cxx b/sc/source/core/opencl/formulagroupcl.cxx
index 134887664a4e..a60f9eda8b7e 100644
--- a/sc/source/core/opencl/formulagroupcl.cxx
+++ b/sc/source/core/opencl/formulagroupcl.cxx
@@ -1607,6 +1607,11 @@ public:
     typedef DynamicKernelSlidingArgument<DynamicKernelStringArgument> StringRange;
     typedef ParallelReductionVectorRef<VectorRef> ParallelNumericRange;
 
+    virtual bool HandleNaNArgument( std::stringstream&, unsigned, SubArguments& ) const
+    {
+        return false;
+    }
+
     virtual void GenSlidingWindowFunction( std::stringstream& ss,
         const std::string& sSymName, SubArguments& vSubArguments ) SAL_OVERRIDE
     {
@@ -1668,18 +1673,25 @@ public:
             }
             if (ocPush == vSubArguments[i]->GetFormulaToken()->GetOpCode())
             {
+                bool bNanHandled = HandleNaNArgument(ss, i, vSubArguments);
+
                 ss << "tmpBottom = " << GetBottom() << ";\n";
-                ss << "if (isNan(";
-                ss << vSubArguments[i]->GenSlidingWindowDeclRef();
-                ss << "))\n";
-                if (ZeroReturnZero())
-                    ss << "    return 0;\n";
-                else
+
+                if (!bNanHandled)
                 {
-                    ss << "    tmp = ";
-                    ss << Gen2("tmpBottom", "tmp") << ";\n";
+                    ss << "if (isNan(";
+                    ss << vSubArguments[i]->GenSlidingWindowDeclRef();
+                    ss << "))\n";
+                    if (ZeroReturnZero())
+                        ss << "    return 0;\n";
+                    else
+                    {
+                        ss << "    tmp = ";
+                        ss << Gen2("tmpBottom", "tmp") << ";\n";
+                    }
+                    ss << "else\n";
                 }
-                ss << "else{\n";
+                ss << "{";
                 ss << "        tmp = ";
                 ss << Gen2(vSubArguments[i]->GenSlidingWindowDeclRef(), "tmp");
                 ss << ";\n";
@@ -2149,9 +2161,35 @@ public:
     virtual std::string GetBottom() SAL_OVERRIDE { return "1.0"; }
     virtual std::string Gen2( const std::string& lhs, const std::string& rhs ) const SAL_OVERRIDE
     {
-        return "(" + lhs + "/" + rhs + ")";
+        return "(" + rhs + "==0 ? CreateDoubleError(errDivisionByZero) : (" + lhs + "/" + rhs + ") )";
     }
     virtual std::string BinFuncName() const SAL_OVERRIDE { return "fdiv"; }
+
+    virtual bool HandleNaNArgument( std::stringstream& ss, unsigned argno, SubArguments& vSubArguments ) const SAL_OVERRIDE
+    {
+        if (argno == 1)
+        {
+            ss <<
+                "if (isnan(" << vSubArguments[argno]->GetName() << "[gid0])) {\n"
+                "    if (GetDoubleErrorValue(" << vSubArguments[argno]->GetName() << "[gid0]) == errNoValue)\n"
+                "        return CreateDoubleError(errDivisionByZero);\n"
+                "}\n";
+            return true;
+        }
+        else if (argno == 0)
+        {
+            ss <<
+                "if (isnan(" << vSubArguments[argno]->GetName() << "[gid0])) {\n"
+                "    if (GetDoubleErrorValue(" << vSubArguments[argno]->GetName() << "[gid0]) == errNoValue) {\n"
+                "        if (" << vSubArguments[1]->GetName() << "[gid0] == 0)\n"
+                "            return CreateDoubleError(errDivisionByZero);\n"
+                "        return 0;\n"
+                "    }\n"
+                "}\n";
+        }
+        return false;
+    }
+
 };
 
 class OpMin : public Reduction
diff --git a/sc/source/core/opencl/formulagroupcl_public.hxx b/sc/source/core/opencl/formulagroupcl_public.hxx
index 3b36770e6014..0ce60ce80e6b 100644
--- a/sc/source/core/opencl/formulagroupcl_public.hxx
+++ b/sc/source/core/opencl/formulagroupcl_public.hxx
@@ -11,6 +11,27 @@
 #define INCLUDED_SC_SOURCE_CORE_OPENCL_FORMULAGROUPCL_PUBLIC_HXX
 
 const char* publicFunc =
+ "\n"
+ "#define errIllegalFPOperation 503 // #NUM!\n"
+ "#define errNoValue 519 // #VALUE!\n"
+ "#define errDivisionByZero 532 // #DIV/0!\n"
+ "\n"
+ "double CreateDoubleError(ulong nErr)\n"
+ "{\n"
+ "    return nan(nErr);\n"
+ "}\n"
+ "\n"
+ "uint GetDoubleErrorValue(double fVal)\n"
+ "{\n"
+ "    if (isfinite(fVal))\n"
+ "        return 0;\n"
+ "    if (isinf(fVal))\n"
+ "        return errIllegalFPOperation; // normal INF\n"
+ "    if (as_ulong(fVal) & 0XFFFF0000u)\n"
+ "        return errNoValue;            // just a normal NAN\n"
+ "    return (as_ulong(fVal) & 0XFFFF); // any other error\n"
+ "}\n"
+ "\n"
  "int isNan(double a) { return isnan(a); }\n"
  "double fsum_count(double a, double b, __private int *p) {\n"
  "    bool t = isNan(a);\n"