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[InstCombine] fold Select with a predicate consists of Icmp connected by And #76363

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775587f
[InstCombine] add simplifySelectWithAndOR
sun-jacobi Dec 25, 2023
4793f28
[InstCombine] update select-and-cmp and select-or-cmp test
sun-jacobi Dec 25, 2023
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73 changes: 46 additions & 27 deletions llvm/lib/Analysis/InstructionSimplify.cpp
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Expand Up @@ -79,46 +79,65 @@ static Value *simplifyInstructionWithOperands(Instruction *I,
const SimplifyQuery &SQ,
unsigned MaxRecurse);

static Value *simplifySelectWithAndOR(Value *Cond, Value *TrueVal,
Value *FalseVal,
CmpInst::Predicate ExpectedPred,
BinaryOperator::BinaryOps BinOpCode,
unsigned int MaxRecurse) {
assert(
(BinOpCode == BinaryOperator::And || BinOpCode == BinaryOperator::Or) &&
"Binary Operator should be And or Or");

assert(
(BinOpCode == BinaryOperator::And && ExpectedPred == ICmpInst::ICMP_EQ) ||
(BinOpCode == BinaryOperator::Or && ExpectedPred == ICmpInst::ICMP_NE));

if (!MaxRecurse)
return nullptr;

auto getSimplifiedValue = [](BinaryOperator::BinaryOps BinOpCode,
Value *TrueVal, Value *FalseVal) {
return BinOpCode == BinaryOperator::Or ? TrueVal : FalseVal;
};

CmpInst::Predicate Pred;
if (match(Cond, m_c_ICmp(Pred, m_Specific(TrueVal), m_Specific(FalseVal))) &&
Pred == ExpectedPred)
return getSimplifiedValue(BinOpCode, TrueVal, FalseVal);

Value *X, *Y;
if (match(Cond, m_c_BinOp(BinOpCode, m_Value(X), m_Value(Y)))) {

auto matchBinOpCode = [&](Value *V) {
return simplifySelectWithAndOR(V, TrueVal, FalseVal, ExpectedPred,
BinOpCode, MaxRecurse - 1);
};

if (matchBinOpCode(X) || matchBinOpCode(Y))
return getSimplifiedValue(BinOpCode, TrueVal, FalseVal);
}

return nullptr;
}

static Value *foldSelectWithBinaryOp(Value *Cond, Value *TrueVal,
Value *FalseVal) {
Value *FalseVal, unsigned int MaxRecurse) {
BinaryOperator::BinaryOps BinOpCode;
if (auto *BO = dyn_cast<BinaryOperator>(Cond))
BinOpCode = BO->getOpcode();
else
return nullptr;

CmpInst::Predicate ExpectedPred, Pred1, Pred2;
CmpInst::Predicate ExpectedPred;
if (BinOpCode == BinaryOperator::Or) {
ExpectedPred = ICmpInst::ICMP_NE;
} else if (BinOpCode == BinaryOperator::And) {
ExpectedPred = ICmpInst::ICMP_EQ;
} else
return nullptr;

// %A = icmp eq %TV, %FV
// %B = icmp eq %X, %Y (and one of these is a select operand)
// %C = and %A, %B
// %D = select %C, %TV, %FV
// -->
// %FV

// %A = icmp ne %TV, %FV
// %B = icmp ne %X, %Y (and one of these is a select operand)
// %C = or %A, %B
// %D = select %C, %TV, %FV
// -->
// %TV
Value *X, *Y;
if (!match(Cond, m_c_BinOp(m_c_ICmp(Pred1, m_Specific(TrueVal),
m_Specific(FalseVal)),
m_ICmp(Pred2, m_Value(X), m_Value(Y)))) ||
Pred1 != Pred2 || Pred1 != ExpectedPred)
return nullptr;

if (X == TrueVal || X == FalseVal || Y == TrueVal || Y == FalseVal)
return BinOpCode == BinaryOperator::Or ? TrueVal : FalseVal;

return nullptr;
return simplifySelectWithAndOR(Cond, TrueVal, FalseVal, ExpectedPred,
BinOpCode, MaxRecurse);
}

/// For a boolean type or a vector of boolean type, return false or a vector
Expand Down Expand Up @@ -4906,7 +4925,7 @@ static Value *simplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
if (Value *V = simplifySelectWithFCmp(Cond, TrueVal, FalseVal, Q))
return V;

if (Value *V = foldSelectWithBinaryOp(Cond, TrueVal, FalseVal))
if (Value *V = foldSelectWithBinaryOp(Cond, TrueVal, FalseVal, MaxRecurse))
return V;

std::optional<bool> Imp = isImpliedByDomCondition(Cond, Q.CxtI, Q.DL);
Expand Down
51 changes: 27 additions & 24 deletions llvm/test/Transforms/InstSimplify/select-and-cmp.ll
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Expand Up @@ -78,6 +78,28 @@ define i32 @select_and_inv_icmp_alt(i32 %x, i32 %y, i32 %z) {
ret i32 %D
}

define i32 @select_and_icmp_ne(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_ne(
; CHECK-NEXT: ret i32 [[X:%.*]]
;
%A = icmp eq i32 %x, %z
%B = icmp ne i32 %y, %z
%C = and i1 %A, %B
%D = select i1 %C, i32 %z, i32 %x
ret i32 %D
}

define i32 @select_and_icmp_ne_alt(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_ne_alt(
; CHECK-NEXT: ret i32 [[Z:%.*]]
;
%A = icmp eq i32 %x, %z
%B = icmp ne i32 %y, %z
%C = and i1 %A, %B
%D = select i1 %C, i32 %x, i32 %z
ret i32 %D
}

define i32 @select_and_inv_icmp(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_inv_icmp(
; CHECK-NEXT: ret i32 [[X:%.*]]
Expand Down Expand Up @@ -115,21 +137,6 @@ define i32 @select_and_icmp_inv(i32 %x, i32 %y, i32 %z) {
; Negative tests
define i32 @select_and_icmp_pred_bad_1(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_1(
; CHECK-NEXT: [[A:%.*]] = icmp eq i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp ne i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = and i1 [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[Z]], i32 [[X]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp eq i32 %x, %z
%B = icmp ne i32 %y, %z
%C = and i1 %A, %B
%D = select i1 %C, i32 %z, i32 %x
ret i32 %D
}

define i32 @select_and_icmp_pred_bad_2(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_2(
; CHECK-NEXT: [[A:%.*]] = icmp ne i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = and i1 [[A]], [[B]]
Expand All @@ -143,8 +150,8 @@ define i32 @select_and_icmp_pred_bad_2(i32 %x, i32 %y, i32 %z) {
ret i32 %D
}

define i32 @select_and_icmp_pred_bad_3(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_3(
define i32 @select_and_icmp_pred_bad_2(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_2(
; CHECK-NEXT: [[A:%.*]] = icmp ne i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp ne i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = and i1 [[A]], [[B]]
Expand All @@ -158,8 +165,8 @@ define i32 @select_and_icmp_pred_bad_3(i32 %x, i32 %y, i32 %z) {
ret i32 %D
}

define i32 @select_and_icmp_pred_bad_4(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_4(
define i32 @select_and_icmp_pred_bad_3(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_3(
; CHECK-NEXT: [[A:%.*]] = icmp eq i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = or i1 [[A]], [[B]]
Expand Down Expand Up @@ -235,11 +242,7 @@ define i32 @select_and_icmp_bad_op_2(i32 %x, i32 %y, i32 %z, i32 %k) {

define i32 @select_and_icmp_alt_bad_1(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_alt_bad_1(
; CHECK-NEXT: [[A:%.*]] = icmp eq i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp ne i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = and i1 [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[X]], i32 [[Z]]
; CHECK-NEXT: ret i32 [[D]]
; CHECK-NEXT: ret i32 [[Z:%.*]]
;
%A = icmp eq i32 %x, %z
%B = icmp ne i32 %y, %z
Expand Down
64 changes: 28 additions & 36 deletions llvm/test/Transforms/InstSimplify/select-or-cmp.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -78,6 +78,28 @@ define i32 @select_or_inv_icmp_alt(i32 %x, i32 %y, i32 %z) {
ret i32 %D
}

define i32 @select_or_icmp_eq(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp_eq(
; CHECK-NEXT: ret i32 [[X:%.*]]
;
%A = icmp ne i32 %x, %z
%B = icmp eq i32 %y, %z
%C = or i1 %A, %B
%D = select i1 %C, i32 %x, i32 %z
ret i32 %D
}

define i32 @select_or_icmp_eq_alt(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp_eq_alt(
; CHECK-NEXT: ret i32 [[Z:%.*]]
;
%A = icmp ne i32 %x, %z
%B = icmp eq i32 %y, %z
%C = or i1 %A, %B
%D = select i1 %C, i32 %z, i32 %x
ret i32 %D
}

define <2 x i8> @select_or_icmp_alt_vec(<2 x i8> %x, <2 x i8> %y, <2 x i8> %z) {
; CHECK-LABEL: @select_or_icmp_alt_vec(
; CHECK-NEXT: ret <2 x i8> [[X:%.*]]
Expand Down Expand Up @@ -129,21 +151,6 @@ define i32 @select_and_icmp_pred_bad_1(i32 %x, i32 %y, i32 %z) {

define i32 @select_and_icmp_pred_bad_2(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_2(
; CHECK-NEXT: [[A:%.*]] = icmp ne i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = or i1 [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[Z]], i32 [[X]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp ne i32 %x, %z
%B = icmp eq i32 %y, %z
%C = or i1 %A, %B
%D = select i1 %C, i32 %z, i32 %x
ret i32 %D
}

define i32 @select_and_icmp_pred_bad_3(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_3(
; CHECK-NEXT: [[A:%.*]] = icmp eq i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = or i1 [[A]], [[B]]
Expand All @@ -157,8 +164,8 @@ define i32 @select_and_icmp_pred_bad_3(i32 %x, i32 %y, i32 %z) {
ret i32 %D
}

define i32 @select_and_icmp_pred_bad_4(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_4(
define i32 @select_and_icmp_pred_bad_3(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_3(
; CHECK-NEXT: [[A:%.*]] = icmp ne i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp ne i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = and i1 [[A]], [[B]]
Expand Down Expand Up @@ -250,21 +257,6 @@ define i32 @select_or_icmp_alt_bad_1(i32 %x, i32 %y, i32 %z) {

define i32 @select_or_icmp_alt_bad_2(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp_alt_bad_2(
; CHECK-NEXT: [[A:%.*]] = icmp ne i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = or i1 [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[X]], i32 [[Z]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp ne i32 %x, %z
%B = icmp eq i32 %y, %z
%C = or i1 %A, %B
%D = select i1 %C, i32 %x, i32 %z
ret i32 %D
}

define i32 @select_or_icmp_alt_bad_3(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp_alt_bad_3(
; CHECK-NEXT: [[A:%.*]] = icmp eq i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = or i1 [[A]], [[B]]
Expand All @@ -278,8 +270,8 @@ define i32 @select_or_icmp_alt_bad_3(i32 %x, i32 %y, i32 %z) {
ret i32 %D
}

define i32 @select_or_icmp_alt_bad_4(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp_alt_bad_4(
define i32 @select_or_icmp_alt_bad_3(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp_alt_bad_3(
; CHECK-NEXT: [[A:%.*]] = icmp ne i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp ne i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = and i1 [[A]], [[B]]
Expand All @@ -293,8 +285,8 @@ define i32 @select_or_icmp_alt_bad_4(i32 %x, i32 %y, i32 %z) {
ret i32 %D
}

define i32 @select_or_icmp_alt_bad_5(i32 %x, i32 %y, i32 %z, i32 %k) {
; CHECK-LABEL: @select_or_icmp_alt_bad_5(
define i32 @select_or_icmp_alt_bad_4(i32 %x, i32 %y, i32 %z, i32 %k) {
; CHECK-LABEL: @select_or_icmp_alt_bad_4(
; CHECK-NEXT: [[A:%.*]] = icmp ne i32 [[X:%.*]], [[K:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp ne i32 [[Y:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[C:%.*]] = or i1 [[A]], [[B]]
Expand Down