Kenneth Graunke <kenn...@whitecape.org> writes: > To validate this code, I ran piglit -t vs quick.tests with the "go spill > everything" debugging code enabled. There was only one regression: > glsl-vs-unroll-explosion simply ran out of registers. This should be > fine in the real world, since no one actually spills every single > register. > > NOTE: This is a candidate for the 9.0 branch. Even if it proves to have > bugs, it's likely better than simply failing to compile. > > Signed-off-by: Kenneth Graunke <kenn...@whitecape.org> > --- > src/mesa/drivers/dri/i965/brw_vec4.h | 3 + > src/mesa/drivers/dri/i965/brw_vec4_emit.cpp | 14 +++ > .../drivers/dri/i965/brw_vec4_reg_allocate.cpp | 128 > ++++++++++++++++++++- > 3 files changed, 144 insertions(+), 1 deletion(-) > > Unfortunately, this assertion fails on the one game that needs it; > oglconform's vertexshader advanced.TestLights test also hits the same > assertion failure (and I would have expected this to fix that test).
I've got a followon patch to fix the assertion failure that I think
could be put in ahead of this one. It doesn't fix the failure to
register allocate, because the live interval analysis is too dumb and
spilling things inside a loop just results in more pressure since all
things used in a loop are live across the entire loop.
> +void
> +vec4_visitor::spill_reg(int spill_reg_nr)
> +{
> + assert(virtual_grf_sizes[spill_reg_nr] == 1);
> + unsigned int spill_offset = c->last_scratch++;
> +
> + /* Generate spill/unspill instructions for the objects being spilled. */
> + foreach_list(node, &this->instructions) {
> + vec4_instruction *inst = (vec4_instruction *) node;
> +
> + for (unsigned int i = 0; i < 3; i++) {
> + if (inst->src[i].file == GRF && inst->src[i].reg == spill_reg_nr) {
> + src_reg spill_reg = inst->src[i];
> + 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(inst, temp, spill_reg, spill_offset);
> + }
temp is otherwise full of garbage and not used by any other instruction,
so I don't think you care about carefully writemasking the read into it.
Other than that, the series is Reviewed-by: Eric Anholt <e...@anholt.net>
pgpiG8sT4xWcz.pgp
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