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[GlobalIsel] Combine G_ADD and G_SUB #92879

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May 23, 2024
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[GlobalIsel] Combine G_ADD and G_SUB #92879

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289b048
[GlobalIsel] Combine integers
tschuett May 21, 2024
287c2ee
address review comments
tschuett May 21, 2024
cbf85de
vectors
tschuett May 22, 2024
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tschuett May 22, 2024
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tschuett May 23, 2024
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75 changes: 74 additions & 1 deletion llvm/include/llvm/Target/GlobalISel/Combine.td
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Original file line number Diff line number Diff line change
Expand Up @@ -1634,6 +1634,78 @@ extract_vector_element_shuffle_vector,
insert_vector_element_extract_vector_element
]>;


// fold ((0-A) + B) -> B-A
def ZeroMinusAPlusB : GICombineRule<
(defs root:$root),
(match (G_SUB $sub, 0, $A),
(G_ADD $root, $sub, $B)),
(apply (G_SUB $root, $B, $A))>;

// fold (A + (0-B)) -> A-B
def APlusZeroMinusB : GICombineRule<
(defs root:$root),
(match (G_SUB $sub, 0, $B),
(G_ADD $root, $A, $sub)),
(apply (G_SUB $root, $A, $B))>;

// fold (A+(B-A)) -> B
def APlusBMinusB : GICombineRule<
(defs root:$root),
(match (G_SUB $sub, $B, $A),
(G_ADD $root, $A, $sub)),
(apply (GIReplaceReg $root, $B))>;

// fold ((B-A)+A) -> B
def BMinusAPlusA : GICombineRule<
(defs root:$root),
(match (G_SUB $sub, $B, $A),
(G_ADD $root, $sub, $A)),
(apply (GIReplaceReg $root, $B))>;

// fold ((A-B)+(C-A)) -> (C-B)
def AMinusBPlusCMinusA : GICombineRule<
(defs root:$root),
(match (G_SUB $sub1, $A, $B),
(G_SUB $sub2, $C, $A),
(G_ADD $root, $sub1, $sub2)),
(apply (G_SUB $root, $C, $B))>;

// fold ((A-B)+(B-C)) -> (A-C)
def AMinusBPlusBMinusC : GICombineRule<
(defs root:$root),
(match (G_SUB $sub1, $A, $B),
(G_SUB $sub2, $B, $C),
(G_ADD $root, $sub1, $sub2)),
(apply (G_SUB $root, $A, $C))>;

// fold (A+(B-(A+C))) to (B-C)
def APlusBMinusAplusC : GICombineRule<
(defs root:$root),
(match (G_ADD $add1, $A, $C),
(G_SUB $sub1, $B, $add1),
(G_ADD $root, $A, $sub1)),
(apply (G_SUB $root, $B, $C))>;

// fold (A+(B-(C+A))) to (B-C)
def APlusBMinusCPlusA : GICombineRule<
(defs root:$root),
(match (G_ADD $add1, $C, $A),
(G_SUB $sub1, $B, $add1),
(G_ADD $root, $A, $sub1)),
(apply (G_SUB $root, $B, $C))>;

def integer_reassoc_combines: GICombineGroup<[
ZeroMinusAPlusB,
APlusZeroMinusB,
APlusBMinusB,
BMinusAPlusA,
AMinusBPlusCMinusA,
AMinusBPlusBMinusC,
APlusBMinusAplusC,
APlusBMinusCPlusA
]>;

// FIXME: These should use the custom predicate feature once it lands.
def undef_combines : GICombineGroup<[undef_to_fp_zero, undef_to_int_zero,
undef_to_negative_one,
Expand Down Expand Up @@ -1691,7 +1763,8 @@ def fma_combines : GICombineGroup<[combine_fadd_fmul_to_fmad_or_fma,
def constant_fold_binops : GICombineGroup<[constant_fold_binop,
constant_fold_fp_binop]>;

def all_combines : GICombineGroup<[trivial_combines, vector_ops_combines,
def all_combines : GICombineGroup<[integer_reassoc_combines, trivial_combines,
vector_ops_combines,
insert_vec_elt_combines, extract_vec_elt_combines, combines_for_extload,
combine_extracted_vector_load,
undef_combines, identity_combines, phi_combines,
Expand Down
252 changes: 252 additions & 0 deletions llvm/test/CodeGen/AArch64/GlobalISel/combine-integer.mir
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Original file line number Diff line number Diff line change
@@ -0,0 +1,252 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -mtriple aarch64 -run-pass=aarch64-prelegalizer-combiner %s -o - | FileCheck %s


---
name: ZeroMinusAPlusB
body: |
bb.0:
liveins: $w0, $w1

; CHECK-LABEL: name: ZeroMinusAPlusB
; CHECK: liveins: $w0, $w1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %a:_(s32) = COPY $w0
; CHECK-NEXT: %b:_(s32) = COPY $w0
; CHECK-NEXT: %add:_(s32) = G_SUB %b, %a
; CHECK-NEXT: $w0 = COPY %add(s32)
; CHECK-NEXT: RET_ReallyLR implicit $w0
%x:_(s32) = COPY $w0
%a:_(s32) = COPY $w0
%b:_(s32) = COPY $w0
%zero:_(s32) = G_CONSTANT i32 0
%sub:_(s32) = G_SUB %zero, %a
%add:_(s32) = G_ADD %sub, %b
$w0 = COPY %add
RET_ReallyLR implicit $w0

...
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Test the multi-use intermediate cases

---
name: ZeroMinusAPlusB_multi_use
body: |
bb.0:
liveins: $w0, $w1

; CHECK-LABEL: name: ZeroMinusAPlusB_multi_use
; CHECK: liveins: $w0, $w1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %a:_(s32) = COPY $w0
; CHECK-NEXT: %b:_(s32) = COPY $w0
; CHECK-NEXT: %zero:_(s32) = G_CONSTANT i32 0
; CHECK-NEXT: %sub:_(s32) = G_SUB %zero, %a
; CHECK-NEXT: %add:_(s32) = G_SUB %b, %a
; CHECK-NEXT: $w0 = COPY %add(s32)
; CHECK-NEXT: $w0 = COPY %sub(s32)
; CHECK-NEXT: RET_ReallyLR implicit $w0
%x:_(s32) = COPY $w0
%a:_(s32) = COPY $w0
%b:_(s32) = COPY $w0
%zero:_(s32) = G_CONSTANT i32 0
%sub:_(s32) = G_SUB %zero, %a
%add:_(s32) = G_ADD %sub, %b
$w0 = COPY %add
$w0 = COPY %sub
RET_ReallyLR implicit $w0

...
---
name: APlusZeroMiunusB
body: |
bb.0:
liveins: $w0, $w1

; CHECK-LABEL: name: APlusZeroMiunusB
; CHECK: liveins: $w0, $w1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %a:_(s64) = COPY $x1
; CHECK-NEXT: %b:_(s64) = COPY $x2
; CHECK-NEXT: %add:_(s64) = G_SUB %a, %b
; CHECK-NEXT: $x0 = COPY %add(s64)
; CHECK-NEXT: RET_ReallyLR implicit $x0
%x:_(s64) = COPY $x0
%a:_(s64) = COPY $x1
%b:_(s64) = COPY $x2
%zero:_(s64) = G_CONSTANT i64 0
%sub:_(s64) = G_SUB %zero, %b
%add:_(s64) = G_ADD %a, %sub
$x0 = COPY %add
RET_ReallyLR implicit $x0

...
---
name: APlusBMinusB
body: |
bb.0:
liveins: $w0, $w1

; CHECK-LABEL: name: APlusBMinusB
; CHECK: liveins: $w0, $w1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %b:_(s64) = COPY $x1
; CHECK-NEXT: $x0 = COPY %b(s64)
; CHECK-NEXT: RET_ReallyLR implicit $x0
%a:_(s64) = COPY $x0
%b:_(s64) = COPY $x1
%zero:_(s64) = G_CONSTANT i64 0
%sub:_(s64) = G_SUB %b, %a
%add:_(s64) = G_ADD %a, %sub
$x0 = COPY %add
RET_ReallyLR implicit $x0

...
---
name: BMinusAPlusA
body: |
bb.0:
liveins: $w0, $w1

; CHECK-LABEL: name: BMinusAPlusA
; CHECK: liveins: $w0, $w1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %b:_(s64) = COPY $x1
; CHECK-NEXT: $x0 = COPY %b(s64)
; CHECK-NEXT: RET_ReallyLR implicit $x0
%a:_(s64) = COPY $x0
%b:_(s64) = COPY $x1
%zero:_(s64) = G_CONSTANT i64 0
%sub:_(s64) = G_SUB %b, %a
%add:_(s64) = G_ADD %sub, %a
$x0 = COPY %add
RET_ReallyLR implicit $x0

...
---
name: AMinusBPlusCMinusA
body: |
bb.0:
liveins: $w0, $w1

; CHECK-LABEL: name: AMinusBPlusCMinusA
; CHECK: liveins: $w0, $w1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %b:_(s64) = COPY $x1
; CHECK-NEXT: %c:_(s64) = COPY $x2
; CHECK-NEXT: %add:_(s64) = G_SUB %c, %b
; CHECK-NEXT: $x0 = COPY %add(s64)
; CHECK-NEXT: RET_ReallyLR implicit $x0
%a:_(s64) = COPY $x0
%b:_(s64) = COPY $x1
%c:_(s64) = COPY $x2
%zero:_(s64) = G_CONSTANT i64 0
%sub2:_(s64) = G_SUB %c, %a
%sub1:_(s64) = G_SUB %a, %b
%add:_(s64) = G_ADD %sub1, %sub2
$x0 = COPY %add
RET_ReallyLR implicit $x0

...
---
name: AMinusBPlusBMinusC
body: |
bb.0:
liveins: $w0, $w1

; CHECK-LABEL: name: AMinusBPlusBMinusC
; CHECK: liveins: $w0, $w1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %a:_(s64) = COPY $x0
; CHECK-NEXT: %c:_(s64) = COPY $x2
; CHECK-NEXT: %add:_(s64) = G_SUB %a, %c
; CHECK-NEXT: $x0 = COPY %add(s64)
; CHECK-NEXT: RET_ReallyLR implicit $x0
%a:_(s64) = COPY $x0
%b:_(s64) = COPY $x1
%c:_(s64) = COPY $x2
%zero:_(s64) = G_CONSTANT i64 0
%sub2:_(s64) = G_SUB %b, %c
%sub1:_(s64) = G_SUB %a, %b
%add:_(s64) = G_ADD %sub1, %sub2
$x0 = COPY %add
RET_ReallyLR implicit $x0


...
---
name: APlusBMinusAplusC
body: |
bb.0:
liveins: $w0, $w1

; CHECK-LABEL: name: APlusBMinusAplusC
; CHECK: liveins: $w0, $w1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %b:_(s64) = COPY $x1
; CHECK-NEXT: %c:_(s64) = COPY $x2
; CHECK-NEXT: %add:_(s64) = G_SUB %b, %c
; CHECK-NEXT: $x0 = COPY %add(s64)
; CHECK-NEXT: RET_ReallyLR implicit $x0
%a:_(s64) = COPY $x0
%b:_(s64) = COPY $x1
%c:_(s64) = COPY $x2
%zero:_(s64) = G_CONSTANT i64 0
%add1:_(s64) = G_ADD %a, %c
%sub1:_(s64) = G_SUB %b, %add1
%add:_(s64) = G_ADD %a, %sub1
$x0 = COPY %add
RET_ReallyLR implicit $x0

...
---
name: APlusBMinusCPlusA
body: |
bb.0:
liveins: $w0, $w1

; CHECK-LABEL: name: APlusBMinusCPlusA
; CHECK: liveins: $w0, $w1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %b:_(s64) = COPY $x1
; CHECK-NEXT: %c:_(s64) = COPY $x2
; CHECK-NEXT: %add:_(s64) = G_SUB %b, %c
; CHECK-NEXT: $x0 = COPY %add(s64)
; CHECK-NEXT: RET_ReallyLR implicit $x0
%a:_(s64) = COPY $x0
%b:_(s64) = COPY $x1
%c:_(s64) = COPY $x2
%zero:_(s64) = G_CONSTANT i64 0
%add1:_(s64) = G_ADD %c, %a
%sub1:_(s64) = G_SUB %b, %add1
%add:_(s64) = G_ADD %a, %sub1
$x0 = COPY %add
RET_ReallyLR implicit $x0

...
---
name: APlusBMinusCPlusA_BV
body: |
bb.0:
liveins: $w0, $w1

; CHECK-LABEL: name: APlusBMinusCPlusA_BV
; CHECK: liveins: $w0, $w1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %a1:_(s64) = COPY $x0
; CHECK-NEXT: %b1:_(s64) = COPY $x1
; CHECK-NEXT: %c1:_(s64) = COPY $x2
; CHECK-NEXT: %b:_(<2 x s64>) = G_BUILD_VECTOR %b1(s64), %ba:_(s64)
; CHECK-NEXT: %c:_(<2 x s64>) = G_BUILD_VECTOR %a1(s64), %c1(s64)
; CHECK-NEXT: %add:_(<2 x s64>) = G_SUB %b, %c
; CHECK-NEXT: $q0 = COPY %add(<2 x s64>)
; CHECK-NEXT: RET_ReallyLR implicit $x0
%a1:_(s64) = COPY $x0
%b1:_(s64) = COPY $x1
%c1:_(s64) = COPY $x2
%a:_(<2 x s64>) = G_BUILD_VECTOR %a1:_(s64), %b1:_(s64)
%b:_(<2 x s64>) = G_BUILD_VECTOR %b1:_(s64), %ba:_(s64)
%c:_(<2 x s64>) = G_BUILD_VECTOR %a1:_(s64), %c1:_(s64)
%zero:_(s64) = G_CONSTANT i64 0
%add1:_(<2 x s64>) = G_ADD %c, %a
%sub1:_(<2 x s64>) = G_SUB %b, %add1
%add:_(<2 x s64>) = G_ADD %a, %sub1
$q0 = COPY %add
RET_ReallyLR implicit $x0
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