Commit Graph

28 Commits

Author SHA1 Message Date
Stanislav Mekhanoshin d4ae470d2e [AMDGPU] Prevent post-RA scheduler from breaking memory clauses
The pre-RA scheduler does load/store clustering, but post-RA
scheduler undoes it. Add mutation to prevent it.

Differential Revision: https://reviews.llvm.org/D38014

llvm-svn: 313670
2017-09-19 20:54:38 +00:00
Alexander Timofeev 982aee6a38 [AMDGPU] Switch scalarize global loads ON by default
Differential revision: https://reviews.llvm.org/D34407

llvm-svn: 307097
2017-07-04 17:32:00 +00:00
NAKAMURA Takumi e4a741376b Revert r307026, "[AMDGPU] Switch scalarize global loads ON by default"
It broke a testcase.

  Failing Tests (1):
      LLVM :: CodeGen/AMDGPU/alignbit-pat.ll

llvm-svn: 307054
2017-07-04 02:14:18 +00:00
Alexander Timofeev ea7f08bee5 [AMDGPU] Switch scalarize global loads ON by default
Differential revision: https://reviews.llvm.org/D34407

llvm-svn: 307026
2017-07-03 14:54:11 +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
Stanislav Mekhanoshin 79da2a7698 [AMDGPU] Remove getBidirectionalReasonRank
This method inverts the Reason field of a scheduling candidate.
It does right comparison between RegCritical and RegExcess, but
everything else is broken. In fact it can prefer less strong reason
such as Weak over RegCritical because Weak > -RegCritical.

The CandReason enum is properly sorted, so just remove artificial
ranking.

Differential Revision: https://reviews.llvm.org/D30557

llvm-svn: 297536
2017-03-11 00:29:27 +00:00
Kyle Butt 7fbec9bdf1 Codegen: Make chains from trellis-shaped CFGs
Lay out trellis-shaped CFGs optimally.
A trellis of the shape below:

  A     B
  |\   /|
  | \ / |
  |  X  |
  | / \ |
  |/   \|
  C     D

would be laid out A; B->C ; D by the current layout algorithm. Now we identify
trellises and lay them out either A->C; B->D or A->D; B->C. This scales with an
increasing number of predecessors. A trellis is a a group of 2 or more
predecessor blocks that all have the same successors.

because of this we can tail duplicate to extend existing trellises.

As an example consider the following CFG:

    B   D   F   H
   / \ / \ / \ / \
  A---C---E---G---Ret

Where A,C,E,G are all small (Currently 2 instructions).

The CFG preserving layout is then A,B,C,D,E,F,G,H,Ret.

The current code will copy C into B, E into D and G into F and yield the layout
A,C,B(C),E,D(E),F(G),G,H,ret

define void @straight_test(i32 %tag) {
entry:
  br label %test1
test1: ; A
  %tagbit1 = and i32 %tag, 1
  %tagbit1eq0 = icmp eq i32 %tagbit1, 0
  br i1 %tagbit1eq0, label %test2, label %optional1
optional1: ; B
  call void @a()
  br label %test2
test2: ; C
  %tagbit2 = and i32 %tag, 2
  %tagbit2eq0 = icmp eq i32 %tagbit2, 0
  br i1 %tagbit2eq0, label %test3, label %optional2
optional2: ; D
  call void @b()
  br label %test3
test3: ; E
  %tagbit3 = and i32 %tag, 4
  %tagbit3eq0 = icmp eq i32 %tagbit3, 0
  br i1 %tagbit3eq0, label %test4, label %optional3
optional3: ; F
  call void @c()
  br label %test4
test4: ; G
  %tagbit4 = and i32 %tag, 8
  %tagbit4eq0 = icmp eq i32 %tagbit4, 0
  br i1 %tagbit4eq0, label %exit, label %optional4
optional4: ; H
  call void @d()
  br label %exit
exit:
  ret void
}

here is the layout after D27742:
straight_test:                          # @straight_test
; ... Prologue elided
; BB#0:                                 # %entry ; A (merged with test1)
; ... More prologue elided
	mr 30, 3
	andi. 3, 30, 1
	bc 12, 1, .LBB0_2
; BB#1:                                 # %test2 ; C
	rlwinm. 3, 30, 0, 30, 30
	beq	 0, .LBB0_3
	b .LBB0_4
.LBB0_2:                                # %optional1 ; B (copy of C)
	bl a
	nop
	rlwinm. 3, 30, 0, 30, 30
	bne	 0, .LBB0_4
.LBB0_3:                                # %test3 ; E
	rlwinm. 3, 30, 0, 29, 29
	beq	 0, .LBB0_5
	b .LBB0_6
.LBB0_4:                                # %optional2 ; D (copy of E)
	bl b
	nop
	rlwinm. 3, 30, 0, 29, 29
	bne	 0, .LBB0_6
.LBB0_5:                                # %test4 ; G
	rlwinm. 3, 30, 0, 28, 28
	beq	 0, .LBB0_8
	b .LBB0_7
.LBB0_6:                                # %optional3 ; F (copy of G)
	bl c
	nop
	rlwinm. 3, 30, 0, 28, 28
	beq	 0, .LBB0_8
.LBB0_7:                                # %optional4 ; H
	bl d
	nop
.LBB0_8:                                # %exit ; Ret
	ld 30, 96(1)                    # 8-byte Folded Reload
	addi 1, 1, 112
	ld 0, 16(1)
	mtlr 0
	blr

The tail-duplication has produced some benefit, but it has also produced a
trellis which is not laid out optimally. With this patch, we improve the layouts
of such trellises, and decrease the cost calculation for tail-duplication
accordingly.

This patch produces the layout A,C,E,G,B,D,F,H,Ret. This layout does have
back edges, which is a negative, but it has a bigger compensating
positive, which is that it handles the case where there are long strings
of skipped blocks much better than the original layout. Both layouts
handle runs of executed blocks equally well. Branch prediction also
improves if there is any correlation between subsequent optional blocks.

Here is the resulting concrete layout:

straight_test:                          # @straight_test
; BB#0:                                 # %entry ; A (merged with test1)
	mr 30, 3
	andi. 3, 30, 1
	bc 12, 1, .LBB0_4
; BB#1:                                 # %test2 ; C
	rlwinm. 3, 30, 0, 30, 30
	bne	 0, .LBB0_5
.LBB0_2:                                # %test3 ; E
	rlwinm. 3, 30, 0, 29, 29
	bne	 0, .LBB0_6
.LBB0_3:                                # %test4 ; G
	rlwinm. 3, 30, 0, 28, 28
	bne	 0, .LBB0_7
	b .LBB0_8
.LBB0_4:                                # %optional1 ; B (Copy of C)
	bl a
	nop
	rlwinm. 3, 30, 0, 30, 30
	beq	 0, .LBB0_2
.LBB0_5:                                # %optional2 ; D (Copy of E)
	bl b
	nop
	rlwinm. 3, 30, 0, 29, 29
	beq	 0, .LBB0_3
.LBB0_6:                                # %optional3 ; F (Copy of G)
	bl c
	nop
	rlwinm. 3, 30, 0, 28, 28
	beq	 0, .LBB0_8
.LBB0_7:                                # %optional4 ; H
	bl d
	nop
.LBB0_8:                                # %exit

Differential Revision: https://reviews.llvm.org/D28522

llvm-svn: 295223
2017-02-15 19:49:14 +00:00
Tom Stellard 00cfa74715 AMDGPU/SI: Don't move copies of immediates to the VALU
Summary:
If we write an immediate to a VGPR and then copy the VGPR to an
SGPR, we can replace the copy with a S_MOV_B32 sgpr, imm, rather than
moving the copy to the SALU.

Reviewers: arsenm

Subscribers: kzhuravl, wdng, nhaehnle, yaxunl, llvm-commits, tony-tye

Differential Revision: https://reviews.llvm.org/D27272

llvm-svn: 288849
2016-12-06 21:13:30 +00:00
Tom Stellard 9fdbec870c AMDGPU/SI: Fix visit order assumption in SIFixSGPRCopies
Summary:
This pass was assuming that when a PHI instruction defined a register
used by another PHI instruction that the defining insstruction would
be legalized before the using instruction.

This assumption was causing the pass to not legalize some PHI nodes
within divergent flow-control.

This fixes a bug that was uncovered by r285762.

Reviewers: nhaehnle, arsenm

Subscribers: kzhuravl, wdng, nhaehnle, yaxunl, tony-tye, llvm-commits

Differential Revision: https://reviews.llvm.org/D26303

llvm-svn: 286676
2016-11-11 23:35:42 +00:00
Tom Stellard 0d23ebe888 AMDGPU/SI: Implement a custom MachineSchedStrategy
Summary:
GCNSchedStrategy re-uses most of GenericScheduler, it's just uses
a different method to compute the excess and critical register
pressure limits.

It's not enabled by default, to enable it you need to pass -misched=gcn
to llc.

Shader DB stats:

32464 shaders in 17874 tests
Totals:
SGPRS: 1542846 -> 1643125 (6.50 %)
VGPRS: 1005595 -> 904653 (-10.04 %)
Spilled SGPRs: 29929 -> 27745 (-7.30 %)
Spilled VGPRs: 334 -> 352 (5.39 %)
Scratch VGPRs: 1612 -> 1624 (0.74 %) dwords per thread
Code Size: 36688188 -> 37034900 (0.95 %) bytes
LDS: 1913 -> 1913 (0.00 %) blocks
Max Waves: 254101 -> 265125 (4.34 %)
Wait states: 0 -> 0 (0.00 %)

Totals from affected shaders:
SGPRS: 1338220 -> 1438499 (7.49 %)
VGPRS: 886221 -> 785279 (-11.39 %)
Spilled SGPRs: 29869 -> 27685 (-7.31 %)
Spilled VGPRs: 334 -> 352 (5.39 %)
Scratch VGPRs: 1612 -> 1624 (0.74 %) dwords per thread
Code Size: 34315716 -> 34662428 (1.01 %) bytes
LDS: 1551 -> 1551 (0.00 %) blocks
Max Waves: 188127 -> 199151 (5.86 %)
Wait states: 0 -> 0 (0.00 %)

Reviewers: arsenm, mareko, nhaehnle, MatzeB, atrick

Subscribers: arsenm, kzhuravl, llvm-commits

Differential Revision: https://reviews.llvm.org/D23688

llvm-svn: 279995
2016-08-29 19:42:52 +00:00
Matt Arsenault 7f9eabd2c2 AMDGPU: Define priorities for register classes
Allocating larger register classes first should give better allocation
results (and more importantly for myself, make the lit tests more stable
with respect to scheduler changes).

Patch by Matthias Braun

llvm-svn: 270312
2016-05-21 03:55:07 +00:00
Tom Stellard c51e4468b7 AMDGPU/SI: Remove wait state handling for SMRD in SIInsertWaits
This was supposed to be part of r268143.

llvm-svn: 268154
2016-04-30 04:04:48 +00:00
Artem Tamazov eb4d5a9b0b [AMDGPU][llvm-mc] Support of Trap Handler registers (TTMP0..11 and TBA/TMA)git status
Tests added along with implemented feature.
Note that there is a small leftover of unecessary MI sheduling issue
(more info in the review). CodeGen/AMDGPU/salu-to-valu.ll updated to fix
the false regression.

TODO: Support for TTMP quads, comma-separated syntax in "[]" and more.

Differential Revision: http://reviews.llvm.org/D17825

llvm-svn: 266205
2016-04-13 16:18:41 +00:00
Tom Stellard ab1d3a9d50 AMDGPU/SI: Insert wait states required after v_readfirstlane on SI
Summary:
We will be able to handle this case much better once the hazard recognizer
is finished, but this conservative implementation  fixes a hang with the piglit
test:

spec/arb_arrays_of_arrays/execution/sampler/fs-nested-struct-arrays-nonconst-nested-arra

Reviewers: arsenm, nhaehnle

Subscribers: arsenm, llvm-commits

Differential Revision: http://reviews.llvm.org/D18988

llvm-svn: 266105
2016-04-12 18:40:43 +00:00
Tom Stellard 467b5b9024 AMDGPU/SI: Use v_readfirstlane to legalize SMRD with VGPR base pointer
Summary:
Instead of trying to replace SMRD instructions with a VGPR base pointer
with an equivalent MUBUF instruction, we now copy the base pointer to
SGPRs using v_readfirstlane.

This is safe to do, because any load selected as an SMRD instruction
has been proven to have a uniform base pointer, so each thread in the
wave will have the same pointer value in VGPRs.

This will fix some errors on VI from trying to replace SMRD instructions
with addr64-enabled MUBUF instructions that don't exist.

Reviewers: arsenm, cfang, nhaehnle

Subscribers: arsenm, llvm-commits

Differential Revision: http://reviews.llvm.org/D17305

llvm-svn: 261385
2016-02-20 00:37:25 +00:00
Tom Stellard bc4497b13c AMDGPU/SI: Detect uniform branches and emit s_cbranch instructions
Reviewers: arsenm

Subscribers: mareko, MatzeB, qcolombet, arsenm, llvm-commits

Differential Revision: http://reviews.llvm.org/D16603

llvm-svn: 260765
2016-02-12 23:45:29 +00:00
Tom Stellard 46937ca4e7 [AMDGPU] Assembler: Swap operands of flat_store instructions to match AMD assembler
Historically, AMD internal sp3 assembler has flat_store* addr, data
format. To match existing code and to enable reuse, change LLVM
definitions to match.  Also update MC and CodeGen tests.

Differential Revision: http://reviews.llvm.org/D16927

Patch by: Nikolay Haustov

llvm-svn: 260694
2016-02-12 17:57:54 +00:00
Matt Arsenault 9c47dd583a AMDGPU: Remove some old intrinsic uses from tests
llvm-svn: 260493
2016-02-11 06:02:01 +00:00
Tom Stellard 5cd09ade38 AMDGPU/SI: Select non-uniform constant addrspace loads to flat instructions for HSA
Summary: This fixes a regression caused by r256282.

Reviewers: arsenm, cfang

Subscribers: arsenm, llvm-commits

Differential Revision: http://reviews.llvm.org/D15736

llvm-svn: 256810
2016-01-05 03:40:16 +00:00
Tom Stellard a6f24c6565 AMDGPU/SI: Select constant loads with non-uniform addresses to MUBUF instructions
Summary:
We were previously selecting all constant loads to SMRD instructions and legalizing
the SMRDs with non-uniform addresses during the SIFixSGPRCopesPass.

This new solution is more simple and also generates much better code, because
the instruction selector is able to take advantage of all the MUBUF addressing
modes that are legalization pass wasn't able to.

We also no longer need to generate v_add_* instructions when we
have a uniform pointer and a non-uniform offset, as this is now folded into the
MUBUF instruction during instruction selection.

Reviewers: arsenm

Subscribers: arsenm, llvm-commits

Differential Revision: http://reviews.llvm.org/D15425

llvm-svn: 255672
2015-12-15 20:55:55 +00:00
Matt Arsenault 4d801cd357 AMDGPU: Split x8 and x16 vector loads instead of scalarize
The one regression in the builtin tests is in the read2 test which now
(again) has many extra copies, but this should be solved once the pass
is replaced with a DAG combine.

llvm-svn: 253974
2015-11-24 12:05:03 +00:00
Matt Arsenault 623e6fd466 AMDGPU: Hack for VS_32 register pressure
For some reason VS_32 ends up factoring into the pressure heuristics
even though we should never see a virtual register with this class.

When SGPRs are reserved for register spilling, this for some reason
triggers reg-crit scheduling.

Setting isAllocatable = 0 may help with this since that seems to remove
it from the default implementation's generated table.

llvm-svn: 252321
2015-11-06 17:54:43 +00:00
Matt Arsenault 73aa8f687a AMDGPU: Fix splitting x16 SMRD loads
When used recursively, this would set the kill flag
on the intermediate step from first splitting
x16 to x8.

llvm-svn: 248741
2015-09-28 20:54:52 +00:00
Matt Arsenault e5d042cd56 AMDGPU: Fix moving SMRD loads with literal offsets on CI
llvm-svn: 248740
2015-09-28 20:54:46 +00:00
Matt Arsenault b378f075a2 AMDGPU: Add testcases
Make sure we are testing moving users
of the moved and split SMRD loads.

llvm-svn: 248738
2015-09-28 20:54:38 +00:00
Matt Arsenault f3c91f573f AMDGPU: Cleanup test
Run instnamer on it, and rename check prefix.

This is in preparation for adding new testcases to cover
bugs on other subtargets.

llvm-svn: 248737
2015-09-28 20:54:32 +00:00
Matt Arsenault 711b390a7c AMDGPU: Assume SMRD access for constant address space
Since r243294 these are selected to SMRD and
moved later if required.

llvm-svn: 244354
2015-08-07 20:18:34 +00:00
Tom Stellard 45bb48ea19 R600 -> AMDGPU rename
llvm-svn: 239657
2015-06-13 03:28:10 +00:00