From 9e5f311efec13a13f27641df3b153f3fcfad741c Mon Sep 17 00:00:00 2001
From: Georg Lehmann <dadschoorse@gmail.com>
Date: Mon, 15 Aug 2022 13:26:23 +0200
Subject: [PATCH] aco: Check that we don't override exec_val operands during
 branching sequence optimization.
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Fixes: baab6f18c91 ("aco: Optimize branching sequence during SSA elimination.")
Signed-off-by: Georg Lehmann <dadschoorse@gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18049>
---
 src/amd/compiler/aco_ssa_elimination.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/amd/compiler/aco_ssa_elimination.cpp b/src/amd/compiler/aco_ssa_elimination.cpp
index ff74585cc67..f82058a6c44 100644
--- a/src/amd/compiler/aco_ssa_elimination.cpp
+++ b/src/amd/compiler/aco_ssa_elimination.cpp
@@ -417,6 +417,13 @@ try_optimize_branching_sequence(ssa_elimination_ctx& ctx, Block& block, const in
       }
    }
 
+   if (save_original_exec) {
+      /* We insert the exec copy before exec_val, so exec_val can't use those registers. */
+      for (const Operand& op : exec_val->operands)
+         if (regs_intersect(exec_copy_def, op))
+            return;
+   }
+
    /* Reassign the instruction to write exec directly. */
    exec_val->definitions[0] = Definition(exec, ctx.program->lane_mask);