Mesa (staging/20.3): aco: add missing usable_read2 check

[GitLab Mirror]

Module: Mesa
Branch: staging/20.3
Commit: d6a63c09b589176c9128aae0eb673bd79c700bfe
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=d6a63c09b589176c9128aae0eb673bd79c700bfe

Author: Rhys Perry <pendingchaos02 at gmail.com>
Date:   Fri Feb 26 16:05:40 2021 +0000

aco: add missing usable_read2 check

A Hitman 2 shader does: read64(local_invocation_index() * 4 - 4). This was
likely emitting a ds_read2_b32 on GFX6. For local_invocation_index()=0,
because the first dword was out-of-bounds, the second was likely also
considered out-of-bounds (even though it's not, at offset 0).

Likely fixes https://gitlab.freedesktop.org/mesa/mesa/-/issues/3882

Signed-off-by: Rhys Perry <pendingchaos02 at gmail.com>
Reviewed-by: Daniel Schürmann <daniel at schuermann.dev>
Fixes: 57e6886f981 ("aco: refactor load_lds to use new helpers")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9332>
(cherry picked from commit 3a72044ece27f6a06d7819bcd6ba3fcc2f786d0c)

---

 .pick_status.json                              | 2 +-
 src/amd/compiler/aco_instruction_selection.cpp | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/.pick_status.json b/.pick_status.json
index e684938e7d9..16074e0657b 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -3154,7 +3154,7 @@
         "description": "aco: add missing usable_read2 check",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "master_sha": null,
         "because_sha": "57e6886f981ca629a863544df253b9ecb3604eec"
     },
diff --git a/src/amd/compiler/aco_instruction_selection.cpp b/src/amd/compiler/aco_instruction_selection.cpp
index 142c75c2b48..5113d689a37 100644
--- a/src/amd/compiler/aco_instruction_selection.cpp
+++ b/src/amd/compiler/aco_instruction_selection.cpp
@@ -3316,7 +3316,7 @@ Temp lds_load_callback(Builder& bld, const LoadEmitInfo &info,
    } else if (bytes_needed >= 8 && align % 8 == 0) {
       size = 8;
       op = aco_opcode::ds_read_b64;
-   } else if (bytes_needed >= 8 && align % 4 == 0 && const_offset % 4 == 0) {
+   } else if (bytes_needed >= 8 && align % 4 == 0 && const_offset % 4 == 0 && usable_read2) {
       size = 8;
       read2 = true;
       op = aco_opcode::ds_read2_b32;