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-rw-r--r--src/mesa/drivers/dri/r300/compiler/radeon_pair_schedule.c28
1 files changed, 25 insertions, 3 deletions
diff --git a/src/mesa/drivers/dri/r300/compiler/radeon_pair_schedule.c b/src/mesa/drivers/dri/r300/compiler/radeon_pair_schedule.c
index ea01bb7881..df67aafe02 100644
--- a/src/mesa/drivers/dri/r300/compiler/radeon_pair_schedule.c
+++ b/src/mesa/drivers/dri/r300/compiler/radeon_pair_schedule.c
@@ -179,8 +179,19 @@ static void commit_instruction(struct schedule_state * s, struct schedule_instru
for(unsigned int i = 0; i < sinst->NumWriteValues; ++i) {
struct reg_value * v = sinst->WriteValues[i];
- for(struct reg_value_reader * r = v->Readers; r; r = r->Next) {
- decrease_dependencies(s, r->Reader);
+ if (v->NumReaders) {
+ for(struct reg_value_reader * r = v->Readers; r; r = r->Next) {
+ decrease_dependencies(s, r->Reader);
+ }
+ } else {
+ /* This happens in instruction sequences of the type
+ * OP r.x, ...;
+ * OP r.x, r.x, ...;
+ * See also the subtlety in how instructions that both
+ * read and write the same register are scanned.
+ */
+ if (v->Next)
+ decrease_dependencies(s, v->Next->Writer);
}
}
}
@@ -360,6 +371,13 @@ static void scan_read(void * data, struct rc_instruction * inst,
if (!v)
return;
+ if (v->Writer == s->Current) {
+ /* The instruction reads and writes to a register component.
+ * In this case, we only want to increment dependencies by one.
+ */
+ return;
+ }
+
DBG("%i: read %i[%i] chan %i\n", s->Current->Instruction->IP, file, index, chan);
struct reg_value_reader * reader = memory_pool_malloc(&s->C->Pool, sizeof(*reader));
@@ -426,8 +444,12 @@ static void schedule_block(struct r300_fragment_program_compiler * c,
DBG("%i: Scanning\n", inst->IP);
- rc_for_all_reads(inst, &scan_read, &s);
+ /* The order of things here is subtle and maybe slightly
+ * counter-intuitive, to account for the case where an
+ * instruction writes to the same register as it reads
+ * from. */
rc_for_all_writes(inst, &scan_write, &s);
+ rc_for_all_reads(inst, &scan_read, &s);
DBG("%i: Has %i dependencies\n", inst->IP, s.Current->NumDependencies);