HLSL: allow promotion from 1-vector types to scalars, e.g, float<-float1

Previously, an error was thrown when assigning a float1 to a scalar float,
or similar for other basic types.  This allows that.

Also, this allows calling functions accepting scalars with float1 params,
so for example sin(float1) will work.  This is a minor change in
HlslParseContext::findFunction().

glslang/Include/Types.h

@@ -1271,6 +1271,7 @@ public:
     virtual       TArraySizes& getArraySizes()       { assert(arraySizes != nullptr); return *arraySizes; }
 
     virtual bool isScalar() const { return ! isVector() && ! isMatrix() && ! isStruct() && ! isArray(); }
+    virtual bool isScalarOrVec1() const { return isScalar() || vector1; }
     virtual bool isVector() const { return vectorSize > 1 || vector1; }
     virtual bool isMatrix() const { return matrixCols ? true : false; }
     virtual bool isArray()  const { return arraySizes != nullptr; }

glslang/MachineIndependent/Intermediate.cpp

@@ -814,8 +814,10 @@ TIntermTyped* TIntermediate::addShapeConversion(TOperator op, const TType& type,
     TOperator constructorOp = mapTypeToConstructorOp(type);
 
     // scalar -> smeared -> vector, or
+    // vec1 -> scalar, or
     // bigger vector -> smaller vector or scalar
     if ((type.isVector() && node->getType().isScalar()) ||
+        (node->getType().isVector() && node->getVectorSize() == 1 && type.isScalar()) ||
         (node->getVectorSize() > type.getVectorSize() && type.isVector()))
         return setAggregateOperator(makeAggregate(node), constructorOp, type, node->getLoc());