From: Eric Anholt <eric@anholt.net>
Date: Wed, 26 Dec 2018 20:54:58 +0000 (-0800)
Subject: v3d: Add a note for a potential performance win on multop/umul24.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=f9bdce99668b62da6ae34e584cfea6f47b402687;p=mesa.git

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

Noticed while debugging a testcase.
---

diff --git a/src/broadcom/compiler/vir_to_qpu.c b/src/broadcom/compiler/vir_to_qpu.c
index 60d39063d53..c66bb84b3fc 100644
--- 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++;