v3d: Add a note for a potential performance win on multop/umul24.

Noticed while debugging a testcase.
2018-12-26 12:54:58 -08:00 · 2018-12-26 12:54:58 -08:00 · f9bdce9966
parent b36757448d
commit f9bdce9966
1 changed files with 4 additions and 0 deletions
--- a/src/broadcom/compiler/vir_to_qpu.c
+++ b/src/broadcom/compiler/vir_to_qpu.c
@ -241,6 +241,10 @@ v3d_generate_code_block(struct v3d_compile *c,
                                src[i] = temp_registers[index];
                                break;
                        case QFILE_UNIF:
+                                /* XXX perf: If the last ldunif we emitted was
+                                 * the same uniform value, skip it.  Common
+                                 * for multop/umul24 sequences.
+                                 */
                                if (!emitted_ldunif) {
                                        new_ldunif_instr(qinst, i);
                                        c->num_uniforms++;