From 4b274068204c7f0bacaa4639f24feb433353b861 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Tue, 14 Feb 2012 12:43:22 -0800 Subject: [PATCH] i965/fs: Take # of components into account in try_rewrite_rhs_to_dst. Commit dc7f449d1ac53a66e6efb56ccf2a5953418a26ca 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 Signed-off-by: Kenneth Graunke --- src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp index e670ba79c18..bf1da9d4588 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp @@ -605,6 +605,12 @@ fs_visitor::try_rewrite_rhs_to_dst(ir_assignment *ir, !src.equals(&last_rhs_inst->dst)) return false; + /* If last_rhs_inst wrote a different number of components than our LHS, + * we can't safely rewrite it. + */ + if (ir->lhs->type->vector_elements != last_rhs_inst->regs_written()) + return false; + /* Success! Rewrite the instruction. */ last_rhs_inst->dst = dst; -- 2.30.2