From 084d10a7027ce8330b8c0502178322b0e1850d3f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timur=20Krist=C3=B3f?= <timur.kristof@gmail.com>
Date: Fri, 3 Feb 2023 00:32:06 +0100
Subject: [PATCH] aco: Remove MTBUF zero operand.
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Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21363>
---
 src/amd/compiler/aco_optimizer.cpp | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/amd/compiler/aco_optimizer.cpp b/src/amd/compiler/aco_optimizer.cpp
index 3e295561d4c..a75ca2a1b4f 100644
--- a/src/amd/compiler/aco_optimizer.cpp
+++ b/src/amd/compiler/aco_optimizer.cpp
@@ -1512,6 +1512,22 @@ label_instruction(opt_ctx& ctx, aco_ptr<Instruction>& instr)
          }
       }
 
+      else if (instr->isMTBUF()) {
+         MTBUF_instruction& mtbuf = instr->mtbuf();
+         while (info.is_temp())
+            info = ctx.info[info.temp.id()];
+
+         if (mtbuf.offen && mtbuf.idxen && i == 1 && info.is_vec() &&
+             info.instr->operands.size() == 2 && info.instr->operands[0].isTemp() &&
+             info.instr->operands[0].regClass() == v1 && info.instr->operands[1].isConstant() &&
+             mtbuf.offset + info.instr->operands[1].constantValue() < 4096) {
+            instr->operands[1] = info.instr->operands[0];
+            mtbuf.offset += info.instr->operands[1].constantValue();
+            mtbuf.offen = false;
+            continue;
+         }
+      }
+
       /* SCRATCH: propagate constants and combine additions */
       else if (instr->isScratch()) {
          FLAT_instruction& scratch = instr->scratch();