Here is the performance data:
```
Using platform: AMD Accelerated Parallel Processing
Using device: gfx900:xnack-
ds_write_b64 aligned by 8: 3.2 sec
ds_write2_b32 aligned by 8: 3.2 sec
ds_write_b16 * 4 aligned by 8: 7.0 sec
ds_write_b8 * 8 aligned by 8: 13.2 sec
ds_write_b64 aligned by 1: 7.3 sec
ds_write2_b32 aligned by 1: 7.5 sec
ds_write_b16 * 4 aligned by 1: 14.0 sec
ds_write_b8 * 8 aligned by 1: 13.2 sec
ds_write_b64 aligned by 2: 7.3 sec
ds_write2_b32 aligned by 2: 7.5 sec
ds_write_b16 * 4 aligned by 2: 7.1 sec
ds_write_b8 * 8 aligned by 2: 13.3 sec
ds_write_b64 aligned by 4: 4.6 sec
ds_write2_b32 aligned by 4: 3.2 sec
ds_write_b16 * 4 aligned by 4: 7.1 sec
ds_write_b8 * 8 aligned by 4: 13.3 sec
ds_read_b64 aligned by 8: 2.3 sec
ds_read2_b32 aligned by 8: 2.2 sec
ds_read_u16 * 4 aligned by 8: 4.8 sec
ds_read_u8 * 8 aligned by 8: 8.6 sec
ds_read_b64 aligned by 1: 4.4 sec
ds_read2_b32 aligned by 1: 7.3 sec
ds_read_u16 * 4 aligned by 1: 14.0 sec
ds_read_u8 * 8 aligned by 1: 8.7 sec
ds_read_b64 aligned by 2: 4.4 sec
ds_read2_b32 aligned by 2: 7.3 sec
ds_read_u16 * 4 aligned by 2: 4.8 sec
ds_read_u8 * 8 aligned by 2: 8.7 sec
ds_read_b64 aligned by 4: 4.4 sec
ds_read2_b32 aligned by 4: 2.3 sec
ds_read_u16 * 4 aligned by 4: 4.8 sec
ds_read_u8 * 8 aligned by 4: 8.7 sec
Using platform: AMD Accelerated Parallel Processing
Using device: gfx1030
ds_write_b64 aligned by 8: 4.4 sec
ds_write2_b32 aligned by 8: 4.3 sec
ds_write_b16 * 4 aligned by 8: 7.9 sec
ds_write_b8 * 8 aligned by 8: 13.0 sec
ds_write_b64 aligned by 1: 23.2 sec
ds_write2_b32 aligned by 1: 23.1 sec
ds_write_b16 * 4 aligned by 1: 44.0 sec
ds_write_b8 * 8 aligned by 1: 13.0 sec
ds_write_b64 aligned by 2: 23.2 sec
ds_write2_b32 aligned by 2: 23.1 sec
ds_write_b16 * 4 aligned by 2: 7.9 sec
ds_write_b8 * 8 aligned by 2: 13.1 sec
ds_write_b64 aligned by 4: 13.5 sec
ds_write2_b32 aligned by 4: 4.3 sec
ds_write_b16 * 4 aligned by 4: 7.9 sec
ds_write_b8 * 8 aligned by 4: 13.1 sec
ds_read_b64 aligned by 8: 3.5 sec
ds_read2_b32 aligned by 8: 3.4 sec
ds_read_u16 * 4 aligned by 8: 5.3 sec
ds_read_u8 * 8 aligned by 8: 8.5 sec
ds_read_b64 aligned by 1: 13.1 sec
ds_read2_b32 aligned by 1: 22.7 sec
ds_read_u16 * 4 aligned by 1: 43.9 sec
ds_read_u8 * 8 aligned by 1: 7.9 sec
ds_read_b64 aligned by 2: 13.1 sec
ds_read2_b32 aligned by 2: 22.7 sec
ds_read_u16 * 4 aligned by 2: 5.6 sec
ds_read_u8 * 8 aligned by 2: 7.9 sec
ds_read_b64 aligned by 4: 13.1 sec
ds_read2_b32 aligned by 4: 3.4 sec
ds_read_u16 * 4 aligned by 4: 5.6 sec
ds_read_u8 * 8 aligned by 4: 7.9 sec
```
GFX10 exposes a different pattern for sub-DWORD load/store performance
than GFX9. On GFX9 it is faster to issue a single unaligned load or
store than a fully split b8 access, where on GFX10 even a full split
is better. However, this is a theoretical only gain because splitting
an access to a sub-dword level will require more registers and packing/
unpacking logic, so ignoring this option it is better to use a single
64 bit instruction on a misaligned data with the exception of 4 byte
aligned data where ds_read2_b32/ds_write2_b32 is better.
Differential Revision: https://reviews.llvm.org/D123956
There is no need to fully scalarize an unaligned operation in
some case, just split it to alignment.
Differential Revision: https://reviews.llvm.org/D123330
GlobalISelEmitter was skipping these patterns when its predicates were
checked. This patch should allow us to select d16_hi stores in
GlobalISel.
Differential Revision: https://reviews.llvm.org/D117762
These actions should only be used for adjusting the register types
(and the memory type as needed to satisfy the register
type). Unaligned accesses should be split as a type of lowering.
This has the effect of improving the code in many cases since now we
produce zextloads instead of separate loads with ands. The load/store
legality rules still seem far more complicated than necessary though.
Using a BufferSize of one for memory ProcResources will result in better
ILP since it more accurately models the dependencies between memory ops
and their consumers on an in-order processor. After this change, the
scheduler will treat the data edges from loads as blocking so that
stalls are guaranteed when waiting for data to be retreaved from memory.
Since we don't actually track waitcnt here, this should do a better job
at modeling their behavior.
Practically, this means that the scheduler will trigger the 'STALL'
heuristic more often.
This type of change needs to be evaluated experimentally. Preliminary
results are positive.
Fixes: SWDEV-282962
Reviewed By: rampitec
Differential Revision: https://reviews.llvm.org/D114777
Use GCNHazardRecognizer in postra sched.
Updated tests for the new schedules.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D109536
Change-Id: Ia86ba2ae168f12fb34b4d8efdab491f84d936cde
G_INSERT legalization is incomplete and doesn't work very
well. Instead try to use sequences of G_MERGE_VALUES/G_UNMERGE_VALUES
padding with undef values (although this can get pretty large).
For the case of load/store narrowing, this is still performing the
load/stores in irregularly sized pieces. It might be cleaner to split
this down into equal sized pieces, and rely on load/store merging to
optimize it.
