Mesa (staging/20.3): aco/ra: fix phi operand renaming

[GitLab Mirror]

Module: Mesa
Branch: staging/20.3
Commit: 8217078f007fb2cda2d82b0b904fbf3e80b9047c
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=8217078f007fb2cda2d82b0b904fbf3e80b9047c

Author: Daniel Schürmann <daniel at schuermann.dev>
Date:   Tue Dec 15 16:21:12 2020 +0100

aco/ra: fix phi operand renaming

In case one operand was renamed and another operand came
from an incomplete phi, it could happen, that the original
name was not restored.

This has no impact on the code, but ensures correct SSA
is maintained during RA.

Cc: mesa-stable
Reviewed-by: Rhys Perry <pendingchaos02 at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8109>
(cherry picked from commit b50d3e5760ca8af775357b4176aaac5991f93cf0)

---

 .pick_status.json                            | 2 +-
 src/amd/compiler/aco_register_allocation.cpp | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/.pick_status.json b/.pick_status.json
index fec41f539a0..7f885dcfd33 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -130,7 +130,7 @@
         "description": "aco/ra: fix phi operand renaming",
         "nominated": true,
         "nomination_type": 0,
-        "resolution": 0,
+        "resolution": 1,
         "master_sha": null,
         "because_sha": null
     },
diff --git a/src/amd/compiler/aco_register_allocation.cpp b/src/amd/compiler/aco_register_allocation.cpp
index 3cf0153c583..c2215da8fc3 100644
--- a/src/amd/compiler/aco_register_allocation.cpp
+++ b/src/amd/compiler/aco_register_allocation.cpp
@@ -1637,6 +1637,11 @@ Temp handle_live_in(ra_ctx& ctx, Temp val, Block* block)
             phi->operands[i].setFixed(ctx.assignments[ops[i].id()].reg);
             if (ops[i].regClass() == new_val.regClass())
                ctx.affinities[new_val.id()] = ops[i].id();
+            /* make sure the operand gets it's original name in case
+             * it comes from an incomplete phi */
+            std::unordered_map<unsigned, phi_info>::iterator it = ctx.phi_map.find(ops[i].id());
+            if (it != ctx.phi_map.end())
+               it->second.uses.emplace(phi.get());
          }
          ctx.assignments.emplace_back();
          assert(ctx.assignments.size() == ctx.program->peekAllocationId());