FastRawViewer and RAWDigger have created a utility that will split the Dual Pixel RAW files from the Canon EOS 5D Mark IV do increase dynamic range of the highlights about +1EV in a single explosure.

FastRAWViewer explains how this works:

Canon 5D Mark IV’s sensor has a somewhat unusual pixel arrangement: each pixel is composed of two subpixels. If Dual Pixel RAW mode is enabled in the camera, the resulting CR2 file contains two images, or two frames: one composite, made from reading both subpixels, summed; and the other is made out of one set of subpixels.

The intended use of this arrangement is to enable some extra editing after the shot: because of the parallax between the subpixels, Canon Digital Photo Professional software allows one to preform microadjustment of focus, bokeh shift, and ghosting reduction.

However, there is one more possible use for a dual-pixel raw, which is not covered by the manufacturer: the second frame, the one that is made out of one set of subpixels, collects half of the light that the composite frame does, as if it was exposed one stop lower compared to the composite frame.

In essence, in Dual Pixel Raw mode, the camera records into one file some equivalent of two shots, bracketed by (approximately) 1 EV.