Emit conditional branches for nir_cf_code_if blocks following a
comparison operation. The NIR compiler does not assign registers to
the comparison operations, and the emitter does not emit any
instructions for them.
Instead, the nir_cf_code_if blocks cause emission of a conditional
branch instruction using the sources and condition flags from the
preceding conditional operation.
Signed-off-by: Philipp Zabel <p.za...@pengutronix.de>
Signed-off-by: Michael Tretter <m.tret...@pengutronix.de>
---
.../drivers/etnaviv/etnaviv_compiler.c | 75 +++++++++++++++++++
src/gallium/drivers/etnaviv/etnaviv_nir.c | 18 +++++
2 files changed, 93 insertions(+)
diff --git a/src/gallium/drivers/etnaviv/etnaviv_compiler.c
b/src/gallium/drivers/etnaviv/etnaviv_compiler.c
index b2499a7e2f6c..0db961c5a751 100644
--- a/src/gallium/drivers/etnaviv/etnaviv_compiler.c
+++ b/src/gallium/drivers/etnaviv/etnaviv_compiler.c
@@ -2162,6 +2162,12 @@ etna_emit_alu(struct etna_compile *c, nir_alu_instr
*instr)
.src[1] = src[1],
});
break;
+ case nir_op_feq:
+ case nir_op_fne:
+ case nir_op_flt:
+ case nir_op_fge:
+ /* Nothing to do, will be handled by the following nir_if */
+ break;
default:
BUG("Unhandled nir_alu_instr: %s\n", info->name);
assert(0);
@@ -2282,6 +2288,72 @@ etna_emit_block(struct etna_compile *c, nir_block
*nblock)
}
}
+static void etna_emit_cf_list(struct etna_compile *c, struct exec_list *list);
+
+static void
+etna_emit_if(struct etna_compile *c, nir_if *nif)
+{
+ struct etna_inst_src src[3] = {};
+
+ assert(nif->condition.is_ssa);
+
+ assert(nif->condition.ssa->parent_instr->type == nir_instr_type_alu);
+ nir_alu_instr *instr = nir_instr_as_alu(nif->condition.ssa->parent_instr);
+
+ assert(instr->op == nir_op_fne || instr->op == nir_op_feq);
+
+ translate_alu_sources(c, instr, src);
+
+ /* The NIR layer should have taken care of this */
+ assert(!etna_src_uniforms_conflict(src[0], src[1]));
+
+ unsigned sp = c->frame_sp++;
+ struct etna_compile_frame *f = &c->frame_stack[sp];
+ /* push IF to stack */
+ f->type = ETNA_COMPILE_FRAME_IF;
+ /* create "else" label */
+ f->lbl_else_idx = alloc_new_label(c);
+ f->lbl_endif_idx = -1;
+
+ /* mark position in instruction stream of label reference so that it can be
+ * filled in in next pass */
+ label_mark_use(c, f->lbl_else_idx);
+
+ /* create conditional branch to else label if not src0 COND src1 */
+ emit_inst(c, &(struct etna_inst){
+ .opcode = INST_OPCODE_BRANCH,
+ .cond = (instr->op == nir_op_fne) ? INST_CONDITION_EQ :
INST_CONDITION_NE,
+ .src[0] = src[0],
+ .src[1] = src[1],
+ /* imm is filled in later */
+ });
+
+ etna_emit_cf_list(c, &nif->then_list);
+
+ /* create "endif" label, and branch to endif label */
+ f->lbl_endif_idx = alloc_new_label(c);
+ label_mark_use(c, f->lbl_endif_idx);
+ emit_inst(c, &(struct etna_inst) {
+ .opcode = INST_OPCODE_BRANCH,
+ .cond = INST_CONDITION_TRUE,
+ /* imm is filled in later */
+ });
+
+ /* mark "else" label at this position in instruction stream */
+ label_place(c, &c->labels[f->lbl_else_idx]);
+
+ etna_emit_cf_list(c, &nif->else_list);
+
+ assert(--c->frame_sp == sp);
+
+ /* assign "endif" or "else" (if no ELSE) label to current position in
+ * instruction stream, pop IF */
+ if (f->lbl_endif_idx != -1)
+ label_place(c, &c->labels[f->lbl_endif_idx]);
+ else
+ label_place(c, &c->labels[f->lbl_else_idx]);
+}
+
static void
etna_emit_cf_list(struct etna_compile *c, struct exec_list *list)
{
@@ -2290,6 +2362,9 @@ etna_emit_cf_list(struct etna_compile *c, struct
exec_list *list)
case nir_cf_node_block:
etna_emit_block(c, nir_cf_node_as_block(node));
break;
+ case nir_cf_node_if:
+ etna_emit_if(c, nir_cf_node_as_if(node));
+ break;
default:
BUG("Unhandled nir node type %d\n", node->type);
assert(0);
diff --git a/src/gallium/drivers/etnaviv/etnaviv_nir.c
b/src/gallium/drivers/etnaviv/etnaviv_nir.c
index af1684ed9091..d8bd282eaeca 100644
--- a/src/gallium/drivers/etnaviv/etnaviv_nir.c
+++ b/src/gallium/drivers/etnaviv/etnaviv_nir.c
@@ -399,6 +399,20 @@ etna_fixup_tex(nir_shader *shader)
}
}
+static bool
+nir_op_is_comparison(nir_op op)
+{
+ switch (op) {
+ case nir_op_flt:
+ case nir_op_fge:
+ case nir_op_feq:
+ case nir_op_fne:
+ return true;
+ default:
+ return false;
+ }
+}
+
/* Return the destination SSA if it should be replaced with a global register,
* or NULL.
*/
@@ -423,6 +437,10 @@ etna_instr_replaceable_ssa_dest(nir_instr *instr)
if (instr->type == nir_instr_type_alu) {
nir_alu_instr *alu = nir_instr_as_alu(instr);
+ /* Comparisons will be turned into conditional jumps */
+ if (nir_op_is_comparison(alu->op))
+ return NULL;
+
return alu->dest.dest.is_ssa ? &alu->dest.dest.ssa : NULL;
}
--
2.17.1
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