diff options
| author | Lionel Landwerlin <lionel.g.landwerlin@intel.com> | 2022-02-16 23:14:15 +0200 |
|---|---|---|
| committer | Dylan Baker <dylan.c.baker@intel.com> | 2022-02-24 14:56:51 -0800 |
| commit | 5998d19a9605f50f22a498eab1e1c4895c433dcc (patch) | |
| tree | 676bb385555a34c8e113bab33b8b748cd7fd7276 | |
| parent | 4aa73d53108d1c2ce4e993cd515c461def2270c5 (diff) | |
nir: fix lower_memcpy
memcpy is divided into chunks that are vec4 sized max. The problem
here happens with a structure of 24 bytes :
struct {
float3 a;
float3 b;
}
If you memcpy that struct, the lowering will emit 2 load/store, one of
sized 8, next one sized 16. But both end up located at offset 0, so we
effectively drop 2 floats.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: a3177cca996145 ("nir: Add a lowering pass to lower memcpy")
Reviewed-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15049>
(cherry picked from commit 768930a73a43e48172df00b6c934de582bd9422b)
| -rw-r--r-- | .pick_status.json | 2 | ||||
| -rw-r--r-- | src/compiler/nir/nir_lower_memcpy.c | 11 |
2 files changed, 8 insertions, 5 deletions
diff --git a/.pick_status.json b/.pick_status.json index abac5691959..09dfa98c269 100644 --- a/.pick_status.json +++ b/.pick_status.json @@ -1876,7 +1876,7 @@ "description": "nir: fix lower_memcpy", "nominated": true, "nomination_type": 1, - "resolution": 0, + "resolution": 1, "main_sha": null, "because_sha": "a3177cca9961452b436b12fd0790c6ffaa8f0eee" }, diff --git a/src/compiler/nir/nir_lower_memcpy.c b/src/compiler/nir/nir_lower_memcpy.c index b7a3f1752cb..768537a3478 100644 --- a/src/compiler/nir/nir_lower_memcpy.c +++ b/src/compiler/nir/nir_lower_memcpy.c @@ -111,11 +111,14 @@ lower_memcpy_impl(nir_function_impl *impl) uint64_t size = nir_src_as_uint(cpy->src[2]); uint64_t offset = 0; while (offset < size) { - uint64_t remaining = offset - size; - /* For our chunk size, we choose the largest power-of-two that - * divides size with a maximum of 16B (a vec4). + uint64_t remaining = size - offset; + /* Find the largest chunk size power-of-two (MSB in remaining) + * and limit our chunk to 16B (a vec4). It's important to do as + * many 16B chunks as possible first so that the index + * computation is correct for + * memcpy_(load|store)_deref_elem_imm. */ - unsigned copy_size = 1u << MIN2(ffsll(remaining) - 1, 4); + unsigned copy_size = 1u << MIN2(util_last_bit64(remaining) - 1, 4); const struct glsl_type *copy_type = copy_type_for_byte_size(copy_size); |