On Wed, 2015-09-30 at 18:41 -0700, Jason Ekstrand wrote:
> Previously, pack_uniform_registers worked based on the size of the uniform
> as given to us when we initially set up the uniforms. However, we have to
> walk through the uniforms and figure out liveness anyway, so we migh as
> well record the number of channels used as we go. This may also allow us
> to pack things tighter in a few cases.
> ---
> src/mesa/drivers/dri/i965/brw_vec4.cpp | 52
> +++++++++++++++++++++++++---------
> 1 file changed, 38 insertions(+), 14 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp
> b/src/mesa/drivers/dri/i965/brw_vec4.cpp
> index 407698f..f0fa07e 100644
> --- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
> @@ -518,11 +518,11 @@ vec4_visitor::split_uniform_registers()
> void
> vec4_visitor::pack_uniform_registers()
> {
> - bool uniform_used[this->uniforms];
> + uint8_t chans_used[this->uniforms];
> int new_loc[this->uniforms];
> int new_chan[this->uniforms];
>
> - memset(uniform_used, 0, sizeof(uniform_used));
> + memset(chans_used, 0, sizeof(chans_used));
> memset(new_loc, 0, sizeof(new_loc));
> memset(new_chan, 0, sizeof(new_chan));
>
> @@ -532,10 +532,36 @@ vec4_visitor::pack_uniform_registers()
> */
> foreach_block_and_inst(block, vec4_instruction, inst, cfg) {
> for (int i = 0 ; i < 3; i++) {
> - if (inst->src[i].file != UNIFORM)
> - continue;
> + if (inst->src[i].file != UNIFORM)
> + continue;
The switch statement below should go before the loop.
> + unsigned readmask;
> + switch (inst->opcode) {
> + case VEC4_OPCODE_PACK_BYTES:
> + case BRW_OPCODE_DP4:
> + case BRW_OPCODE_DPH:
> + readmask = 0xf;
> + break;
> + case BRW_OPCODE_DP3:
> + readmask = 0x7;
> + break;
> + case BRW_OPCODE_DP2:
> + readmask = 0x3;
> + break;
I don't know if there are other opcodes that could also be
special-handled like these, but if there are we are only missing the
opportunity to do tighter packing for them (which we are not doing now
anyway)...
Reviewed-by: Iago Toral Quiroga <ito...@igalia.com>
> + default:
> + readmask = inst->dst.writemask;
> + break;
> + }
> +
> + int reg = inst->src[i].reg;
> +
> + for (int c = 0; c < 4; c++) {
> + if (!(readmask & (1 << c)))
> + continue;
>
> - uniform_used[inst->src[i].reg] = true;
> + chans_used[reg] = MAX2(chans_used[reg],
> + BRW_GET_SWZ(inst->src[i].swizzle, c) + 1);
> + }
> }
> }
>
> @@ -546,17 +572,15 @@ vec4_visitor::pack_uniform_registers()
> */
> for (int src = 0; src < uniforms; src++) {
> assert(src < uniform_array_size);
> - int size = this->uniform_vector_size[src];
> + int size = chans_used[src];
>
> - if (!uniform_used[src]) {
> - this->uniform_vector_size[src] = 0;
> - continue;
> - }
> + if (size == 0)
> + continue;
>
> int dst;
> /* Find the lowest place we can slot this uniform in. */
> for (dst = 0; dst < src; dst++) {
> - if (this->uniform_vector_size[dst] + size <= 4)
> + if (chans_used[dst] + size <= 4)
> break;
> }
>
> @@ -565,7 +589,7 @@ vec4_visitor::pack_uniform_registers()
> new_chan[src] = 0;
> } else {
> new_loc[src] = dst;
> - new_chan[src] = this->uniform_vector_size[dst];
> + new_chan[src] = chans_used[dst];
>
> /* Move the references to the data */
> for (int j = 0; j < size; j++) {
> @@ -573,8 +597,8 @@ vec4_visitor::pack_uniform_registers()
> stage_prog_data->param[src * 4 + j];
> }
>
> - this->uniform_vector_size[dst] += size;
> - this->uniform_vector_size[src] = 0;
> + chans_used[dst] += size;
> + chans_used[src] = 0;
> }
>
> new_uniform_count = MAX2(new_uniform_count, dst + 1);
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