pan/bi: Use canonical next_clause_prefetch
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7081>
diff --git a/src/panfrost/bifrost/bi_pack.c b/src/panfrost/bifrost/bi_pack.c
index 8fef1a4..7e758a5 100644
--- a/src/panfrost/bifrost/bi_pack.c
+++ b/src/panfrost/bifrost/bi_pack.c
@@ -48,7 +48,7 @@
.back_to_back = clause->back_to_back,
.no_end_of_shader = (next_1 != NULL),
.terminate_discarded_threads = is_fragment,
- .branch_cond = clause->branch_conditional || clause->back_to_back,
+ .next_clause_prefetch = clause->next_clause_prefetch,
.datareg_writebarrier = clause->data_register_write_barrier,
.datareg = clause->data_register,
.scoreboard_deps = scoreboard_deps,
@@ -59,8 +59,6 @@
.suppress_nan = true,
};
- header.branch_cond |= header.back_to_back;
-
uint64_t u = 0;
memcpy(&u, &header, sizeof(header));
return u;
diff --git a/src/panfrost/bifrost/bi_print.c b/src/panfrost/bifrost/bi_print.c
index a97663c..e30ef8a 100644
--- a/src/panfrost/bifrost/bi_print.c
+++ b/src/panfrost/bifrost/bi_print.c
@@ -410,7 +410,10 @@
}
if (!clause->back_to_back)
- fprintf(fp, " nbb %s", clause->branch_conditional ? "branch-cond" : "branch-uncond");
+ fprintf(fp, " nbb");
+
+ if (!clause->next_clause_prefetch)
+ fprintf(fp, " no_prefetch");
if (clause->data_register_write_barrier)
fprintf(fp, " drwb");
diff --git a/src/panfrost/bifrost/bi_schedule.c b/src/panfrost/bifrost/bi_schedule.c
index a336e5e..ea526a1 100644
--- a/src/panfrost/bifrost/bi_schedule.c
+++ b/src/panfrost/bifrost/bi_schedule.c
@@ -227,11 +227,13 @@
u->constants[0] = ins->constant.u64;
/* No indirect jumps yet */
- if (ins->type == BI_BRANCH) {
+ if (ins->type == BI_BRANCH)
u->branch_constant = true;
- u->branch_conditional =
- (ins->cond != BI_COND_ALWAYS);
- }
+
+ /* We always prefetch except unconditional branches */
+ u->next_clause_prefetch = !(
+ (ins->type == BI_BRANCH) &&
+ (ins->cond == BI_COND_ALWAYS));
u->clause_type = bi_clause_type_for_ins(ins);
u->block = (struct bi_block *) block;
diff --git a/src/panfrost/bifrost/bifrost.h b/src/panfrost/bifrost/bifrost.h
index acb1035..d57df43 100644
--- a/src/panfrost/bifrost/bifrost.h
+++ b/src/panfrost/bifrost/bifrost.h
@@ -88,11 +88,10 @@
* for fragment shaders for standard GL behaviour of DISCARD. */
unsigned terminate_discarded_threads : 1;
- // If backToBack is off:
- // - true for conditional branches and fallthrough
- // - false for unconditional branches
- // The blob seems to always set it to true if back-to-back is on.
- unsigned branch_cond : 1;
+ /* If set, the hardware may prefetch the next clause. If false, the
+ * hardware may not. Clear for unconditional branches. */
+ unsigned next_clause_prefetch : 1;
+
// This bit is set when the next clause writes to the data register of some
// previous clause.
unsigned datareg_writebarrier: 1;
diff --git a/src/panfrost/bifrost/compiler.h b/src/panfrost/bifrost/compiler.h
index eaacf74..c13a7e9 100644
--- a/src/panfrost/bifrost/compiler.h
+++ b/src/panfrost/bifrost/compiler.h
@@ -400,7 +400,10 @@
* the emitted code it's always set if back-to-bit is, whereas we use
* the actual value (without back-to-back so to speak) internally */
bool back_to_back;
- bool branch_conditional;
+
+ /* Can we prefetch the next clause? Usually it makes sense, except for
+ * clauses ending in unconditional branches */
+ bool next_clause_prefetch;
/* Assigned data register */
unsigned data_register;
diff --git a/src/panfrost/bifrost/disassemble.c b/src/panfrost/bifrost/disassemble.c
index 0b972b4..83be8d5 100644
--- a/src/panfrost/bifrost/disassemble.c
+++ b/src/panfrost/bifrost/disassemble.c
@@ -109,10 +109,6 @@
if (!header.back_to_back) {
fprintf(fp, "nbb ");
- if (header.branch_cond)
- fprintf(fp, "branch-cond ");
- else
- fprintf(fp, "branch-uncond ");
}
if (header.suppress_inf)
@@ -146,6 +142,9 @@
if (header.terminate_discarded_threads)
fprintf(fp, "td ");
+ if (header.next_clause_prefetch)
+ fprintf(fp, "ncph ");
+
fprintf(fp, "\n");
if (verbose) {
