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Serguei Katkov
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[InstCombine] Add support for max(a,b) + min(a,b) => a + b. Re-land.
The same optimization for max(a,b) * min(a,b) => a * b is added. Correctness check: uadd: https://alive2.llvm.org/ce/z/2rXDek sadd: https://alive2.llvm.org/ce/z/zNu_er uadd + nuw/nsw: https://alive2.llvm.org/ce/z/EaiNjB sadd + nuw/nsw: https://alive2.llvm.org/ce/z/w_2Nrs umul: https://alive2.llvm.org/ce/z/dgXRLr smul: https://alive2.llvm.org/ce/z/hBjGzz umul + nuw/nsw: https://alive2.llvm.org/ce/z/EaiNjB smul + nuw/nsw: https://alive2.llvm.org/ce/z/87MNeS Reviewed By: goldstein.w.n Differential Revision: https://reviews.llvm.org/D147296
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-36
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4 files changed

+26
-36
lines changed

‎llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1554,6 +1554,13 @@ Instruction *InstCombinerImpl::visitAdd(BinaryOperator &I) {
15541554
if (Instruction *Ashr = foldAddToAshr(I))
15551555
return Ashr;
15561556

1557+
// min(A, B) + max(A, B) => A + B.
1558+
if (match(&I, m_CombineOr(m_c_Add(m_SMax(m_Value(A), m_Value(B)),
1559+
m_c_SMin(m_Deferred(A), m_Deferred(B))),
1560+
m_c_Add(m_UMax(m_Value(A), m_Value(B)),
1561+
m_c_UMin(m_Deferred(A), m_Deferred(B))))))
1562+
return BinaryOperator::CreateWithCopiedFlags(Instruction::Add, A, B, &I);
1563+
15571564
// TODO(jingyue): Consider willNotOverflowSignedAdd and
15581565
// willNotOverflowUnsignedAdd to reduce the number of invocations of
15591566
// computeKnownBits.

‎llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -471,6 +471,13 @@ Instruction *InstCombinerImpl::visitMul(BinaryOperator &I) {
471471
if (Instruction *Ext = narrowMathIfNoOverflow(I))
472472
return Ext;
473473

474+
// min(X, Y) * max(X, Y) => X * Y.
475+
if (match(&I, m_CombineOr(m_c_Mul(m_SMax(m_Value(X), m_Value(Y)),
476+
m_c_SMin(m_Deferred(X), m_Deferred(Y))),
477+
m_c_Mul(m_UMax(m_Value(X), m_Value(Y)),
478+
m_c_UMin(m_Deferred(X), m_Deferred(Y))))))
479+
return BinaryOperator::CreateWithCopiedFlags(Instruction::Mul, X, Y, &I);
480+
474481
bool Changed = false;
475482
if (!HasNSW && willNotOverflowSignedMul(Op0, Op1, I)) {
476483
Changed = true;

‎llvm/test/Transforms/InstCombine/add-min-max.ll

Lines changed: 6 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -9,9 +9,7 @@ declare i32 @llvm.umin.i32(i32 %a, i32 %b)
99
define i32 @uadd_min_max(i32 %a, i32 %b) {
1010
; CHECK-LABEL: @uadd_min_max(
1111
; CHECK-NEXT: entry:
12-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.umax.i32(i32 [[A:%.*]], i32 [[B:%.*]])
13-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.umin.i32(i32 [[A]], i32 [[B]])
14-
; CHECK-NEXT: [[RES:%.*]] = add i32 [[MIN]], [[MAX]]
12+
; CHECK-NEXT: [[RES:%.*]] = add i32 [[A:%.*]], [[B:%.*]]
1513
; CHECK-NEXT: ret i32 [[RES]]
1614
;
1715
entry:
@@ -24,9 +22,7 @@ entry:
2422
define i32 @uadd_min_max_comm(i32 %a, i32 %b) {
2523
; CHECK-LABEL: @uadd_min_max_comm(
2624
; CHECK-NEXT: entry:
27-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.umax.i32(i32 [[B:%.*]], i32 [[A:%.*]])
28-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.umin.i32(i32 [[A]], i32 [[B]])
29-
; CHECK-NEXT: [[RES:%.*]] = add i32 [[MIN]], [[MAX]]
25+
; CHECK-NEXT: [[RES:%.*]] = add i32 [[B:%.*]], [[A:%.*]]
3026
; CHECK-NEXT: ret i32 [[RES]]
3127
;
3228
entry:
@@ -39,9 +35,7 @@ entry:
3935
define i32 @uadd_min_max_nuw_nsw(i32 %a, i32 %b) {
4036
; CHECK-LABEL: @uadd_min_max_nuw_nsw(
4137
; CHECK-NEXT: entry:
42-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.umax.i32(i32 [[A:%.*]], i32 [[B:%.*]])
43-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.umin.i32(i32 [[A]], i32 [[B]])
44-
; CHECK-NEXT: [[RES:%.*]] = add nuw nsw i32 [[MIN]], [[MAX]]
38+
; CHECK-NEXT: [[RES:%.*]] = add nuw nsw i32 [[A:%.*]], [[B:%.*]]
4539
; CHECK-NEXT: ret i32 [[RES]]
4640
;
4741
entry:
@@ -54,9 +48,7 @@ entry:
5448
define i32 @sadd_min_max(i32 %a, i32 %b) {
5549
; CHECK-LABEL: @sadd_min_max(
5650
; CHECK-NEXT: entry:
57-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.smax.i32(i32 [[A:%.*]], i32 [[B:%.*]])
58-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.smin.i32(i32 [[A]], i32 [[B]])
59-
; CHECK-NEXT: [[RES:%.*]] = add i32 [[MIN]], [[MAX]]
51+
; CHECK-NEXT: [[RES:%.*]] = add i32 [[A:%.*]], [[B:%.*]]
6052
; CHECK-NEXT: ret i32 [[RES]]
6153
;
6254
entry:
@@ -69,9 +61,7 @@ entry:
6961
define i32 @sadd_min_max_comm(i32 %a, i32 %b) {
7062
; CHECK-LABEL: @sadd_min_max_comm(
7163
; CHECK-NEXT: entry:
72-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.smax.i32(i32 [[B:%.*]], i32 [[A:%.*]])
73-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.smin.i32(i32 [[A]], i32 [[B]])
74-
; CHECK-NEXT: [[RES:%.*]] = add i32 [[MIN]], [[MAX]]
64+
; CHECK-NEXT: [[RES:%.*]] = add i32 [[B:%.*]], [[A:%.*]]
7565
; CHECK-NEXT: ret i32 [[RES]]
7666
;
7767
entry:
@@ -84,9 +74,7 @@ entry:
8474
define i32 @sadd_min_max_nuw_nsw(i32 %a, i32 %b) {
8575
; CHECK-LABEL: @sadd_min_max_nuw_nsw(
8676
; CHECK-NEXT: entry:
87-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.smax.i32(i32 [[A:%.*]], i32 [[B:%.*]])
88-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.smin.i32(i32 [[A]], i32 [[B]])
89-
; CHECK-NEXT: [[RES:%.*]] = add nuw nsw i32 [[MIN]], [[MAX]]
77+
; CHECK-NEXT: [[RES:%.*]] = add nuw nsw i32 [[A:%.*]], [[B:%.*]]
9078
; CHECK-NEXT: ret i32 [[RES]]
9179
;
9280
entry:

‎llvm/test/Transforms/InstCombine/mul-min-max.ll

Lines changed: 6 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -9,9 +9,7 @@ declare i32 @llvm.umin.i32(i32 %a, i32 %b)
99
define i32 @umul_min_max(i32 %a, i32 %b) {
1010
; CHECK-LABEL: @umul_min_max(
1111
; CHECK-NEXT: entry:
12-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.umax.i32(i32 [[A:%.*]], i32 [[B:%.*]])
13-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.umin.i32(i32 [[A]], i32 [[B]])
14-
; CHECK-NEXT: [[RES:%.*]] = mul i32 [[MIN]], [[MAX]]
12+
; CHECK-NEXT: [[RES:%.*]] = mul i32 [[A:%.*]], [[B:%.*]]
1513
; CHECK-NEXT: ret i32 [[RES]]
1614
;
1715
entry:
@@ -24,9 +22,7 @@ entry:
2422
define i32 @umul_min_max_comm(i32 %a, i32 %b) {
2523
; CHECK-LABEL: @umul_min_max_comm(
2624
; CHECK-NEXT: entry:
27-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.umax.i32(i32 [[B:%.*]], i32 [[A:%.*]])
28-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.umin.i32(i32 [[A]], i32 [[B]])
29-
; CHECK-NEXT: [[RES:%.*]] = mul i32 [[MIN]], [[MAX]]
25+
; CHECK-NEXT: [[RES:%.*]] = mul i32 [[B:%.*]], [[A:%.*]]
3026
; CHECK-NEXT: ret i32 [[RES]]
3127
;
3228
entry:
@@ -39,9 +35,7 @@ entry:
3935
define i32 @umul_min_max_nuw_nsw(i32 %a, i32 %b) {
4036
; CHECK-LABEL: @umul_min_max_nuw_nsw(
4137
; CHECK-NEXT: entry:
42-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.umax.i32(i32 [[A:%.*]], i32 [[B:%.*]])
43-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.umin.i32(i32 [[A]], i32 [[B]])
44-
; CHECK-NEXT: [[RES:%.*]] = mul nuw nsw i32 [[MIN]], [[MAX]]
38+
; CHECK-NEXT: [[RES:%.*]] = mul nuw nsw i32 [[A:%.*]], [[B:%.*]]
4539
; CHECK-NEXT: ret i32 [[RES]]
4640
;
4741
entry:
@@ -54,9 +48,7 @@ entry:
5448
define i32 @smul_min_max(i32 %a, i32 %b) {
5549
; CHECK-LABEL: @smul_min_max(
5650
; CHECK-NEXT: entry:
57-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.smax.i32(i32 [[A:%.*]], i32 [[B:%.*]])
58-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.smin.i32(i32 [[A]], i32 [[B]])
59-
; CHECK-NEXT: [[RES:%.*]] = mul i32 [[MIN]], [[MAX]]
51+
; CHECK-NEXT: [[RES:%.*]] = mul i32 [[A:%.*]], [[B:%.*]]
6052
; CHECK-NEXT: ret i32 [[RES]]
6153
;
6254
entry:
@@ -69,9 +61,7 @@ entry:
6961
define i32 @smul_min_max_comm(i32 %a, i32 %b) {
7062
; CHECK-LABEL: @smul_min_max_comm(
7163
; CHECK-NEXT: entry:
72-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.smax.i32(i32 [[B:%.*]], i32 [[A:%.*]])
73-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.smin.i32(i32 [[A]], i32 [[B]])
74-
; CHECK-NEXT: [[RES:%.*]] = mul i32 [[MIN]], [[MAX]]
64+
; CHECK-NEXT: [[RES:%.*]] = mul i32 [[B:%.*]], [[A:%.*]]
7565
; CHECK-NEXT: ret i32 [[RES]]
7666
;
7767
entry:
@@ -84,9 +74,7 @@ entry:
8474
define i32 @smul_min_max_nuw_nsw(i32 %a, i32 %b) {
8575
; CHECK-LABEL: @smul_min_max_nuw_nsw(
8676
; CHECK-NEXT: entry:
87-
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.smax.i32(i32 [[A:%.*]], i32 [[B:%.*]])
88-
; CHECK-NEXT: [[MIN:%.*]] = call i32 @llvm.smin.i32(i32 [[A]], i32 [[B]])
89-
; CHECK-NEXT: [[RES:%.*]] = mul nuw nsw i32 [[MIN]], [[MAX]]
77+
; CHECK-NEXT: [[RES:%.*]] = mul nuw nsw i32 [[A:%.*]], [[B:%.*]]
9078
; CHECK-NEXT: ret i32 [[RES]]
9179
;
9280
entry:

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