From 965bdf7db299fd8ba4afd5e4809b3fdf170e1b96 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Sch=C3=BCrmann?= <daniel@schuermann.dev>
Date: Fri, 29 Apr 2022 17:05:10 +0200
Subject: [PATCH] aco/ra: fix live-range splits of phi definitions

It could happen that at the time of a live-range split,
a phi was not yet placed in the new instruction vector,
and thus, instead of renamed, a new phi was created.

Fixes: dEQP-VK.subgroups.ballot_broadcast.compute.subgroupbroadcast_i8vec2
Cc: mesa-stable

Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16248>
(cherry picked from commit 58bd9a379efada22efc3d1ac0848f681c2dd811a)
---
 .pick_status.json                            |  2 +-
 src/amd/compiler/aco_register_allocation.cpp | 29 ++++++++------------
 2 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/.pick_status.json b/.pick_status.json
index 036b0226072..aab3dbe8275 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -229,7 +229,7 @@
         "description": "aco/ra: fix live-range splits of phi definitions",
         "nominated": true,
         "nomination_type": 0,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null
     },
diff --git a/src/amd/compiler/aco_register_allocation.cpp b/src/amd/compiler/aco_register_allocation.cpp
index 9560aed7742..a6867af82be 100644
--- a/src/amd/compiler/aco_register_allocation.cpp
+++ b/src/amd/compiler/aco_register_allocation.cpp
@@ -2052,12 +2052,18 @@ void
 get_regs_for_phis(ra_ctx& ctx, Block& block, RegisterFile& register_file,
                   std::vector<aco_ptr<Instruction>>& instructions, IDSet& live_in)
 {
-   /* assign phis with all-matching registers to that register */
+   /* move all phis to instructions */
    for (aco_ptr<Instruction>& phi : block.instructions) {
       if (!is_phi(phi))
          break;
+      if (!phi->definitions[0].isKill())
+         instructions.emplace_back(std::move(phi));
+   }
+
+   /* assign phis with all-matching registers to that register */
+   for (aco_ptr<Instruction>& phi : instructions) {
       Definition& definition = phi->definitions[0];
-      if (definition.isKill() || definition.isFixed())
+      if (definition.isFixed())
          continue;
 
       if (!phi->operands[0].isTemp())
@@ -2079,11 +2085,9 @@ get_regs_for_phis(ra_ctx& ctx, Block& block, RegisterFile& register_file,
    }
 
    /* try to find a register that is used by at least one operand */
-   for (aco_ptr<Instruction>& phi : block.instructions) {
-      if (!is_phi(phi))
-         break;
+   for (aco_ptr<Instruction>& phi : instructions) {
       Definition& definition = phi->definitions[0];
-      if (definition.isKill() || definition.isFixed())
+      if (definition.isFixed())
          continue;
 
       /* use affinity if available */
@@ -2116,25 +2120,16 @@ get_regs_for_phis(ra_ctx& ctx, Block& block, RegisterFile& register_file,
    }
 
    /* find registers for phis where the register was blocked or no operand was assigned */
-   for (aco_ptr<Instruction>& phi : block.instructions) {
-      if (!is_phi(phi))
-         break;
-
+   for (aco_ptr<Instruction>& phi : instructions) {
       Definition& definition = phi->definitions[0];
-      if (definition.isKill())
+      if (definition.isFixed())
          continue;
 
-      if (definition.isFixed()) {
-         instructions.emplace_back(std::move(phi));
-         continue;
-      }
-
       definition.setFixed(
          get_reg_phi(ctx, live_in, register_file, instructions, block, phi, definition.getTemp()));
 
       register_file.fill(definition);
       ctx.assignments[definition.tempId()].set(definition);
-      instructions.emplace_back(std::move(phi));
    }
 }