From: Kenneth Graunke Date: Wed, 10 Dec 2014 08:52:50 +0000 (-0800) Subject: i965/vec4: Drop writemasks on scratch reads. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=23caba862a001f82ef352307a79bebf7ef910959;p=mesa.git i965/vec4: Drop writemasks on scratch reads. This code is complete nonsense and has apparently existed since I first implemented register spilling in the VS two years ago. Scratch reads are SEND messages, which ignore the destination writemask. The comment about "data that may not have been written to scratch" is also confusing - we always spill whole 4x2 registers, so such data simply does not exist. We can safely ignore the writemask. Signed-off-by: Kenneth Graunke Reviewed-by: Matt Turner --- diff --git a/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp b/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp index 828a70e2752..e8e2185ac1a 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp +++ b/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp @@ -335,14 +335,6 @@ vec4_visitor::spill_reg(int spill_reg_nr) inst->src[i].reg = virtual_grf_alloc(1); dst_reg temp = dst_reg(inst->src[i]); - /* Only read the necessary channels, to avoid overwriting the rest - * with data that may not have been written to scratch. - */ - temp.writemask = 0; - for (int c = 0; c < 4; c++) - temp.writemask |= (1 << BRW_GET_SWZ(inst->src[i].swizzle, c)); - assert(temp.writemask != 0); - emit_scratch_read(block, inst, temp, spill_reg, spill_offset); } }