Bug 104690

Mesa 8e4efdc895eacca931b94a0c1fa01aae5c34463b introduced a regression on G33 for the following tests:

piglit.spec.!opengl 1_4.draw-batch
piglit.spec.!opengl 1_4.gl-1_4-dlist-multidrawarrays

commit 8e4efdc895eacca931b94a0c1fa01aae5c34463b
Author: Brian Paul <brianp@vmware.com>
Date:   Fri Jan 12 13:18:25 2018 -0700

    vbo: optimize some display list drawing (v2)

    The vbo_save_vertex_list structure records one or more glBegin/End
    primitives which all have the same vertex format.


    To draw these primitives, we setup the vertex array state, then
    issue the drawing command.  Before, the 'start' vertex was typically
    zero and we used the vertex array pointer to indicate where the
    vertex data starts.

    This patch checks if the vertex buffer offset is an exact multiple of
    the vertex size.  If so, that means we can use zero-based vertex array
    pointers and use the draw's start value to indicate where the vertex
    data starts.

    This means a series of display list drawing commands may have
    identical vertex array state.  This will get filtered out by the
    Gallium CSO module so we can issue a tight series of drawing commands
    without state changes to the device.

    Note that this also works for a series of glCallList commands (not
    just one list that contains multiple glBegin/End pairs).

    No Piglit or conform changes.

    v2: minor fixes suggested by Ian.

    Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>