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Merged
merged 5 commits into from
Jun 12, 2025
Merged

ABCD dead branch elimination (upper bounds checks) #191

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3cda1e8
ABCD (upper bounds checks)
m-demare May 6, 2025
e59e72a
Save unreachable blocks instead of dead edges
m-demare Jun 2, 2025
24bbdbe
Small changes and improvements to merge this PR now (and implement th…
m-demare Jun 11, 2025
370eb73
Add AIGraphAlgorithms dependency
m-demare Jun 12, 2025
c3addfc
Merge branch 'main' into pi-nodes/abcd
m-demare Jun 12, 2025
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10 changes: 8 additions & 2 deletions BaselineOfDruid/BaselineOfDruid.class.st
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Original file line number Diff line number Diff line change
Expand Up @@ -17,8 +17,14 @@ BaselineOfDruid >> baseline: spec [
className: 'BaselineOfVMMaker';
repository: 'github://pharo-project/opensmalltalk-vm:druid' ].

spec
package: 'Druid' with: [ spec requires: #('PharoVM') ];
spec
baseline: 'AIGraphAlgorithms'
with: [ spec
className: 'BaselineOfAIGraphAlgorithms';
repository: 'github://pharo-ai/graph-algorithms:master' ].

spec
package: 'Druid' with: [ spec requires: #('PharoVM' 'AIGraphAlgorithms') ];
package: 'Druid-Tests' with: [ spec requires: 'Druid' ];
package: 'Druid-UI' with: [ spec requires: #('Druid' 'Druid-Tests') ].

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187 changes: 187 additions & 0 deletions Druid-Tests/DRPiABCDDeadBranchEliminationTest.class.st
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Original file line number Diff line number Diff line change
@@ -0,0 +1,187 @@
Class {
#name : 'DRPiABCDDeadBranchEliminationTest',
#superclass : 'DRPiNodesTest',
#category : 'Druid-Tests-Optimizations',
#package : 'Druid-Tests',
#tag : 'Optimizations'
}

{ #category : 'tests' }
DRPiABCDDeadBranchEliminationTest >> testABCDGraph [
| cfg b_i b_end limit0 limit1 st0 st1 b_while b_for j1 b_if1 st3 limit3 j0 b_if2 t0 b_if2_after_check2 b_if2_after_check1 j4 cmp_for dummyOperand1 jmp_for b_check_failed |

"This is the running example in the ABCD paper, reproduced it just to have something to validate our results agains
The code is kinda ugly, I don't know if there's a nicer way to build this self-referencial/cyclic IRs"

" /->------------------------------------------------------------------------------------->-\
/ V--<-------------------<-\ /->---------------------/->--\
|b_i| -> |b_while| -> |b_if1| -> |b_for| -> |b_if2| -> |b_if2_after_check1| -> |b_if2_after_check2| -> |b_end|
\-<------------------------------------------------------<-/
"

"Check Figure 3 in ABCD: Eliminating Array Bounds Checks on Demand for it to make *a bit* more sense"
Comment on lines +16 to +22
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cfg := DRControlFlowGraph new.

b_end := cfg newBasicBlockWith: [ :block | block storeSInt64: 2 at: 888 ].
b_check_failed := cfg newBasicBlockWith: [ :block | block storeSInt64: 2 at: 777 ].

b_i := cfg newBasicBlockWith: [ :block |
dummyOperand1 := block copy: 1234.
limit0 := block loadFramePointer.
st0 := block copy: -1.
].
cfg initialBasicBlock jumpTo: b_i.

b_if2_after_check2 := cfg newBasicBlockWith: [ :block |
j4 := block add: 1 to: dummyOperand1 "j1".
].

b_if2_after_check1 := cfg newBasicBlockWith: [ :block | |check|
t0 := block add: 1 to: dummyOperand1 "j1".
check := block less: t0 than: limit0.
block jumpIf: check to: b_if2_after_check2 ifFalseTo: b_check_failed.
].
b_if2 := cfg newBasicBlockWith: [ :block | |check|
check := block less: dummyOperand1 "j1" than: limit0.
block jumpIf: check to: b_if2_after_check1 ifFalseTo: b_check_failed.
].

b_for := cfg newBasicBlock.

b_if2_after_check2 jumpTo: b_for.

b_if1 := cfg newBasicBlockWith: [ :block |
st3 := block add: 1 to: dummyOperand1 "st1".
limit3 := block subtract: 1 from: dummyOperand1 "limit1".
j0 := block copy: st3.
block jumpTo: b_for.
].

cmp_for := b_for less: dummyOperand1 than: limit3.
jmp_for := b_for jumpIf: cmp_for to: b_if2 ifFalseTo: b_i.

j1 := b_for phiWithVariables: {1234 asDRValue . 4567 asDRValue }.
cmp_for replaceOperand: dummyOperand1 by: j1.

b_if2_after_check2 instructions first replaceOperand: dummyOperand1 by: j1.
b_if2_after_check1 instructions first replaceOperand: dummyOperand1 by: j1.
b_if2 instructions first replaceOperand: dummyOperand1 by: j1.

j1 replaceOperand: j1 operands first by: j0.
j1 replaceOperand: j1 operands second by: j4.

b_while := cfg newBasicBlockWith: [ :block | |cmp|
limit1 := block phiWithVariables: {}.
st1 := block phiWithVariables: {}.
cmp := block less: st1 than: limit1.
block jumpIf: cmp to: b_if1 ifFalseTo: b_end
].

b_if1 instructions first replaceOperand: dummyOperand1 by: st1.
b_if1 instructions second replaceOperand: dummyOperand1 by: limit1.

b_i jumpTo: b_while.

jmp_for falseBranch removePredecessor: jmp_for basicBlock.
jmp_for newFalseBranch: b_while.
jmp_for basicBlock predecessors add: jmp_for basicBlock predecessors removeFirst.

limit1 operands: {limit0. limit3}.
st1 operands: {st0. st3}.

cfg validate.


self optimize: cfg with: { DRPiABCDDeadBranchElimination }.


self assert: b_if2 successors size equals: 1.
self assert: b_if2 successors unique ~= b_check_failed.

self assert: b_if2_after_check1 successors size equals: 1.
self assert: b_if2 successors unique ~= b_check_failed.

self assert: (cfg blocks includes: b_check_failed) not.

]

{ #category : 'tests' }
DRPiABCDDeadBranchEliminationTest >> testABCDWithAdditionOverSameVariable [

"
/->-|b_end0| (unreachable)
|b_i| -> |b_if1| -> |b_end1|
"

| cfg b_end0 b_end1 b_i x y b_if1 |
cfg := DRControlFlowGraph new.

b_end0 := cfg newBasicBlockWith: [ :block | block storeSInt64: 2 at: 777 ].
b_end1 := cfg newBasicBlockWith: [ :block | block storeSInt64: 2 at: 888 ].

b_i := cfg newBasicBlockWith: [ :block |
x := block loadSInt64: 111.
y := block add: 1 to: x.
].

b_if1 := cfg newBasicBlockWith: [ :block | |cmp|
cmp := block less: y than: x.
block jumpIf: cmp to: b_end0 ifFalseTo: b_end1
].

cfg initialBasicBlock jumpTo: b_i.
b_i jumpTo: b_if1.


self optimize: cfg with: { DRPiABCDDeadBranchElimination }.

self skip. "Pretty sure this needs lower bounds check algorithm to work"
self deny: (cfg blocks includes: b_end0).
self assert: (cfg blocks includes: b_end1).

self assert: b_if1 endInstruction isJump.
self assert: b_if1 endInstruction isConditionalBranch not.
self assert: b_if1 endInstruction target equals: b_end1.

]

{ #category : 'tests' }
DRPiABCDDeadBranchEliminationTest >> testABCDWithSubstractionOverSameVariable [

"
/->-|b_end0|
|b_i| -> |b_if1| -> |b_end1| (unreachable)
"

| cfg b_end0 b_end1 b_i x y b_if1 |
cfg := DRControlFlowGraph new.

b_end0 := cfg newBasicBlockWith: [ :block | block storeSInt64: 2 at: 777 ].
b_end1 := cfg newBasicBlockWith: [ :block | block storeSInt64: 2 at: 888 ].

b_i := cfg newBasicBlockWith: [ :block |
x := block loadSInt64: 111.
y := block subtract: 1 from: x.
].

b_if1 := cfg newBasicBlockWith: [ :block | |cmp|
cmp := block less: y than: x.
block jumpIf: cmp to: b_end0 ifFalseTo: b_end1
].

cfg initialBasicBlock jumpTo: b_i.
b_i jumpTo: b_if1.


self optimize: cfg with: { DRPiABCDDeadBranchElimination }.


self assert: (cfg blocks includes: b_end0).
self deny: (cfg blocks includes: b_end1).

self assert: b_if1 endInstruction isJump.
self assert: b_if1 endInstruction isConditionalBranch not.
self assert: b_if1 endInstruction target equals: b_end0.

]
86 changes: 0 additions & 86 deletions Druid-Tests/DRPiNodesInsertionTest.class.st
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Original file line number Diff line number Diff line change
Expand Up @@ -6,92 +6,6 @@ Class {
#tag : 'Optimizations'
}

{ #category : 'tests' }
DRPiNodesInsertionTest >> testABCDGraph [
| cfg b_i b_end limit0 limit1 st0 st1 b_while b_for j1 b_if1 st3 limit3 j0 b_if2 t0 b_if2_after_check2 b_if2_after_check1 j4 cmp_for dummyOperand1 jmp_for |

"This is the running example in the ABCD paper, reproduced it just to have something to validate our results agains
The code is kinda ugly, I don't know if there's a nicer way to build this self-referencial/cyclic IRs"

" /->------------------------------------------------------------------------------------->-\
/ V--<-------------------<-\ /->---------------------/->--\
|b_i| -> |b_while| -> |b_if1| -> |b_for| -> |b_if2| -> |b_if2_after_check1| -> |b_if2_after_check2| -> |b_end|
\-<------------------------------------------------------<-/
"

"Check Figure 3 in ABCD: Eliminating Array Bounds Checks on Demand for it to make *a bit* more sense"

cfg := DRControlFlowGraph new.

b_end := cfg newBasicBlockWith: [ :block | block storeSInt64: 2 at: 888 ].

b_i := cfg newBasicBlockWith: [ :block |
dummyOperand1 := block copy: 1234.
limit0 := block loadFramePointer.
st0 := block copy: -1.
].
cfg initialBasicBlock jumpTo: b_i.

b_if2_after_check2 := cfg newBasicBlockWith: [ :block |
j4 := block add: 10 to: dummyOperand1 "j1".
].

b_if2_after_check1 := cfg newBasicBlockWith: [ :block | |check|
t0 := block add: 11 to: dummyOperand1 "j1".
check := block less: t0 than: limit0.
block jumpIf: check to: b_if2_after_check2 ifFalseTo: b_end.
].
b_if2 := cfg newBasicBlockWith: [ :block | |check|
check := block less: dummyOperand1 "j1" than: limit0.
block jumpIf: check to: b_if2_after_check1 ifFalseTo: b_end.
].

b_for := cfg newBasicBlock.

b_if2_after_check2 jumpTo: b_for.

cmp_for := b_for less: dummyOperand1 than: limit0.
jmp_for := b_for jumpIf: cmp_for to: b_if2 ifFalseTo: b_i.

j1 := b_for phiWithVariables: {1234 asDRValue . 4567 asDRValue }.
cmp_for replaceOperand: dummyOperand1 by: j1.

b_if2_after_check2 instructions first replaceOperand: dummyOperand1 by: j1.
b_if2_after_check1 instructions first replaceOperand: dummyOperand1 by: j1.
b_if2 instructions first replaceOperand: dummyOperand1 by: j1.

b_if1 := cfg newBasicBlockWith: [ :block |
st3 := block add: 12 to: dummyOperand1 "st1".
limit3 := block subtract: 1 from: dummyOperand1 "limit1".
j0 := block copy: st3.
block jumpTo: b_for.
].

j1 replaceOperand: j1 operands first by: j0.
j1 replaceOperand: j1 operands second by: j4.

b_while := cfg newBasicBlockWith: [ :block | |cmp|
limit1 := block phiWith: {limit0. limit3}.
st1 := block phiWith: {st0. st3}.
cmp := block less: st1 than: limit1.
block jumpIf: cmp to: b_if1 ifFalseTo: b_end
].

b_if1 instructions first replaceOperand: dummyOperand1 by: st1.
b_if1 instructions second replaceOperand: dummyOperand1 by: limit1.

b_i jumpTo: b_while.

jmp_for falseBranch removePredecessor: jmp_for basicBlock.
jmp_for newFalseBranch: b_while.
jmp_for basicBlock predecessors add: jmp_for basicBlock predecessors removeFirst.


cfg validate.
self insertPiNodes: cfg.

]

{ #category : 'tests' }
DRPiNodesInsertionTest >> testInsertPiNodesEqualsCondition [

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4 changes: 1 addition & 3 deletions Druid-Tests/DRPiNodesTest.class.st
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Expand Up @@ -23,9 +23,7 @@ DRPiNodesTest >> insertPiNodes: cfg [
DRPiNodesTest >> optimize: cfg with: optimisations [

self insertPiNodes: cfg.

cfg applyOptimisation: ((optimisations collect: [ :o | o new ]) reduce: [ :o1 :o2 | o1 then: o2 ]).

cfg applyOptimisation: (optimisations reduce: [ :o1 :o2 | o1 then: o2 ]).
cfg applyOptimisation: DRCopyPropagation new.
cfg applyOptimisation: DRDeadCodeElimination new.
]
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