Commit dc7f449d1a introduced a new method
for avoiding MOVs: try to rewrite the destination of the instruction
that produced the RHS so it writes into the LHS.
Unfortunately, this is not safe for swizzled texturing operations, as
they return a set of four contiguous registers. Consider the following:
(assign (x)
(var_ref vec_ctor_x)
(swiz x (tex vec4 (var_ref m_sampY) (var_ref m_cordY) 0 1 ())))
In this case, the source and destination registers are equal, since
reg_offset is 0 for both. Yet, this is only a partial move: the texture
operation generates four registers, and the LHS only covers one.
Fixes color distortion in XBMC when using GLSL shaders.
NOTE: This is a candidate for the 8.0 branch (with the previous commit).
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44333
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Kenneth Graunke
4b27406820