From 98b0122e0a194e0d6c5d3eb05fd3f29a5286b3b3 Mon Sep 17 00:00:00 2001 From: Francisco Jerez Date: Wed, 15 Jul 2015 17:31:04 +0300 Subject: [PATCH] i965/fs: Don't attempt to copy the useless half of oMask for SIMD8 FB writes. There's no need to initialize the wrong half of oMask in the payload when we're doing an 8-wide framebuffer write because it will be ignored by the hardware anyway. By doing it this way we can let the SIMD lowering pass split the sample_mask source as a regular per-channel source, otherwise we would have to introduce some sort of per-instruction source query or use fs_inst::header_size for the lowering pass to be able to find out whether some source is header-like, and leave the source untouched in that case. As a bonus this achieves the same purpose as the previous code without making use of the SET_OMASK pseudo-instruction, which will be removed in a future commit. Reviewed-by: Jason Ekstrand Reviewed-by: Kenneth Graunke --- src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp index 564d694..a0dcca0 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp @@ -1499,6 +1499,7 @@ fs_visitor::emit_single_fb_write(const fs_builder &bld, assert(stage == MESA_SHADER_FRAGMENT); brw_wm_prog_data *prog_data = (brw_wm_prog_data*) this->prog_data; brw_wm_prog_key *key = (brw_wm_prog_key*) this->key; + const fs_builder ubld = bld.group(exec_size, use_2nd_half); int header_size = 2, payload_header_size; /* We can potentially have a message length of up to 15, so we have to set @@ -1536,14 +1537,24 @@ fs_visitor::emit_single_fb_write(const fs_builder &bld, } if (prog_data->uses_omask) { - assert(this->sample_mask.file != BAD_FILE); - /* Hand over gl_SampleMask. Only lower 16 bits are relevant. Since - * it's unsinged single words, one vgrf is always 16-wide. - */ sources[length] = fs_reg(GRF, alloc.allocate(1), - BRW_REGISTER_TYPE_UW); - bld.exec_all().annotate("FB write oMask") - .emit(FS_OPCODE_SET_OMASK, sources[length], this->sample_mask); + BRW_REGISTER_TYPE_UD); + + /* Hand over gl_SampleMask. Only the lower 16 bits of each channel are + * relevant. Since it's unsigned single words one vgrf is always + * 16-wide, but only the lower or higher 8 channels will be used by the + * hardware when doing a SIMD8 write depending on whether we have + * selected the subspans for the first or second half respectively. + */ + fs_reg sample_mask = this->sample_mask; + assert(sample_mask.file != BAD_FILE && type_sz(sample_mask.type) == 4); + sample_mask.type = BRW_REGISTER_TYPE_UW; + sample_mask.stride *= 2; + + ubld.annotate("FB write oMask") + .MOV(half(retype(sources[length], BRW_REGISTER_TYPE_UW), + use_2nd_half), + half(sample_mask, use_2nd_half)); length++; } @@ -1590,7 +1601,6 @@ fs_visitor::emit_single_fb_write(const fs_builder &bld, if (payload.dest_depth_reg) sources[length++] = fs_reg(brw_vec8_grf(payload.dest_depth_reg, 0)); - const fs_builder ubld = bld.group(exec_size, use_2nd_half); fs_inst *load; fs_inst *write; if (devinfo->gen >= 7) { -- 2.7.4