aco: fix emitting discard when the program just ends

For fragment shaders that only contain a discard, the exec mask has
to be zero'd and everything discarded.

It seems unnecessary to emit an export here because if the FS has no
exports, the compiler already emits a null export at the end.

Fixes incorrect hair rendering in Detroit: Become Human.

fossil-db (Sienna Cichlid):
Totals from 3 (0.00% of 149839) affected shaders:
CodeSize: 2896 -> 2872 (-0.83%)
Instrs: 556 -> 553 (-0.54%)
Latency: 29266 -> 29214 (-0.18%)
InvThroughput: 3374 -> 3372 (-0.06%)

Cc: 21.1 mesa-stable
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10955>
This commit is contained in:
Samuel Pitoiset 2021-05-24 17:05:30 +02:00 committed by Marge Bot
parent 5283c6d47b
commit 729ebe4b17

View file

@ -5287,11 +5287,8 @@ void visit_discard(isel_context* ctx, nir_intrinsic_instr *instr)
*/
if (!ctx->cf_info.parent_if.is_divergent) {
/* program just ends here */
ctx->block->kind |= block_kind_uniform;
bld.exp(aco_opcode::exp, Operand(v1), Operand(v1), Operand(v1), Operand(v1),
0 /* enabled mask */, 9 /* dest */,
false /* compressed */, true/* done */, true /* valid mask */);
bld.sopp(aco_opcode::s_endpgm);
ctx->block->kind |= block_kind_uses_discard_if;
bld.pseudo(aco_opcode::p_discard_if, Operand(0xFFFFFFFFu));
// TODO: it will potentially be followed by a branch which is dead code to sanitize NIR phis
} else {
ctx->block->kind |= block_kind_discard;