From 42663165a26e4f172755c7b9f9b3ce9235118ca8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Sch=C3=BCrmann?= <daniel@schuermann.dev>
Date: Fri, 6 Mar 2026 12:01:44 +0100
Subject: [PATCH] vtn: set nir_loop::do_while during spirv_to_nir()

Acked-by: Timothy Arceri <tarceri@itsqueeze.com>
Reviewed-by: Georg Lehmann <dadschoorse@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40349>
---
 src/compiler/spirv/vtn_structured_cfg.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/compiler/spirv/vtn_structured_cfg.c b/src/compiler/spirv/vtn_structured_cfg.c
index 5424c8dc55a..34db3519490 100644
--- a/src/compiler/spirv/vtn_structured_cfg.c
+++ b/src/compiler/spirv/vtn_structured_cfg.c
@@ -1220,6 +1220,14 @@ vtn_emit_branch(struct vtn_builder *b, const struct vtn_block *block,
       struct vtn_construct *loop = block->parent->innermost_loop;
       vtn_assert(loop);
       vtn_emit_break_for_construct(b, block, loop);
+
+      /* If this is a conditional back-edge, flag this loop as do-while loop.
+       * The same applies to single-block loops.
+       */
+      if (block->parent->type == vtn_construct_type_continue ||
+          vtn_is_single_block_loop(loop)) {
+         loop->nloop->do_while = true;
+      }
       break;
    }