From a8879daf9c3d187822ef2784567a15197a830c2c Mon Sep 17 00:00:00 2001
From: Faith Ekstrand <faith.ekstrand@collabora.com>
Date: Wed, 1 Apr 2026 13:15:02 -0400
Subject: [PATCH] pan/bi: Add a bi_try_compose_swizzles() helper

Reviewed-by: Lorenzo Rossi <lorenzo.rossi@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40720>
---
 src/panfrost/compiler/bifrost/compiler.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/panfrost/compiler/bifrost/compiler.h b/src/panfrost/compiler/bifrost/compiler.h
index 828d7319784..fcbe016c0b1 100644
--- a/src/panfrost/compiler/bifrost/compiler.h
+++ b/src/panfrost/compiler/bifrost/compiler.h
@@ -183,6 +183,22 @@ bi_swizzle_from_byte_channels(const unsigned byte_channels[4],
    }
 }
 
+static inline bool
+bi_try_compose_swizzles(enum bi_swizzle *ab_out,
+                        enum bi_swizzle a, enum bi_swizzle b)
+{
+   unsigned a_bytes[4], b_bytes[4];
+   bi_swizzle_to_byte_channels(a, a_bytes);
+   bi_swizzle_to_byte_channels(b, b_bytes);
+
+   unsigned ab_bytes[4];
+   for (unsigned i = 0; i < 4; i++) {
+      ab_bytes[i] = b_bytes[a_bytes[i]];
+   }
+
+   return bi_swizzle_from_byte_channels(ab_bytes, ab_out);
+}
+
 static inline enum bi_swizzle
 bi_swizzle_from_half(bool x, bool y)
 {