From 34993085f4a7bf10e7eec9c8e334aa4b2dc8ff4f Mon Sep 17 00:00:00 2001
From: Simon Perretta <simon.perretta@imgtec.com>
Date: Thu, 21 Aug 2025 11:34:09 +0100
Subject: [PATCH] pco/opt: disable back-propagation of indexed registers

Signed-off-by: Simon Perretta <simon.perretta@imgtec.com>
Acked-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36412>
---
 src/imagination/pco/pco_opt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/imagination/pco/pco_opt.c b/src/imagination/pco/pco_opt.c
index e08863db3d2..26caf8b9953 100644
--- a/src/imagination/pco/pco_opt.c
+++ b/src/imagination/pco/pco_opt.c
@@ -258,6 +258,9 @@ static inline bool try_back_prop_instr(struct pco_use *uses, pco_instr *instr)
 
    pco_ref *pdest_from = &use->instr->dest[0];
 
+   if (pco_ref_is_idx_reg(*pdest_from))
+      return false;
+
    if (pco_ref_is_reg(*pdest_from) &&
        pco_ref_get_reg_class(*pdest_from) == PCO_REG_CLASS_PIXOUT) {
       return false;