Commit Graph

6 Commits

Author SHA1 Message Date
Jay Foad 6c0204c794 [AMDGPU] Mark s_barrier as having side effects but not accessing memory.
Summary:
This fixes poor scheduling in a function containing a barrier and a few
load instructions.

Without this fix, ScheduleDAGInstrs::buildSchedGraph adds an artificial
edge in the dependency graph from the barrier instruction to the exit
node representing live-out latency, with a latency of about 500 cycles.
Because of this it thinks the critical path through the graph also has
a latency of about 500 cycles. And because of that it does not think
that any of the load instructions are on the critical path, so it
schedules them with no regard for their (80 cycle) latency, which gives
poor results.

Reviewers: arsenm, dstuttard, tpr, nhaehnle

Subscribers: kzhuravl, jvesely, wdng, yaxunl, t-tye, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67218

llvm-svn: 371192
2019-09-06 10:07:28 +00:00
Nicolai Haehnle 2710171a15 AMDGPU: Write LDS objects out as global symbols in code generation
Summary:
The symbols use the processor-specific SHN_AMDGPU_LDS section index
introduced with a previous change. The linker is then expected to resolve
relocations, which are also emitted.

Initially disabled for HSA and PAL environments until they have caught up
in terms of linker and runtime loader.

Some notes:

- The llvm.amdgcn.groupstaticsize intrinsics can no longer be lowered
  to a constant at compile times, which means some tests can no longer
  be applied.

  The current "solution" is a terrible hack, but the intrinsic isn't
  used by Mesa, so we can keep it for now.

- We no longer know the full LDS size per kernel at compile time, which
  means that we can no longer generate a relevant error message at
  compile time. It would be possible to add a check for the size of
  individual variables, but ultimately the linker will have to perform
  the final check.

Change-Id: If66dbf33fccfbf3609aefefa2558ac0850d42275

Reviewers: arsenm, rampitec, t-tye, b-sumner, jsjodin

Subscribers: qcolombet, kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61494

llvm-svn: 364297
2019-06-25 11:52:30 +00:00
Stanislav Mekhanoshin c90347d760 [AMDGPU] Generate range metadata for workitem id
If workgroup size is known inform llvm about range returned by local
id  and local size queries.

Differential Revision: https://reviews.llvm.org/D31804

llvm-svn: 300102
2017-04-12 20:48:56 +00:00
Matt Arsenault 3dbeefa978 AMDGPU: Mark all unspecified CC functions in tests as amdgpu_kernel
Currently the default C calling convention functions are treated
the same as compute kernels. Make this explicit so the default
calling convention can be changed to a non-kernel.

Converted with perl -pi -e 's/define void/define amdgpu_kernel void/'
on the relevant test directories (and undoing in one place that actually
wanted a non-kernel).

llvm-svn: 298444
2017-03-21 21:39:51 +00:00
Tom Stellard c2ff0eb697 AMDGPU/SI: Improve SILoadStoreOptimizer and run it before the scheduler
Summary:
The SILoadStoreOptimizer can now look ahead more then one instruction when
looking for instructions to merge, which greatly improves the number of
loads/stores that we are able to merge.

Moving the pass before scheduling avoids increasing register pressure after
the scheduler, so that the scheduler's register pressure estimates will be
more accurate.  It also gives more consistent results, since it is no longer
affected by minor scheduling changes.

Reviewers: arsenm

Subscribers: arsenm, kzhuravl, llvm-commits

Differential Revision: https://reviews.llvm.org/D23814

llvm-svn: 279991
2016-08-29 19:15:22 +00:00
Matt Arsenault 4c519d3518 AMDGPU/R600: Replace barrier intrinsics
llvm-svn: 275870
2016-07-18 18:34:59 +00:00