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[InstCombine] Fold (!iszero(A & K1) & !iszero(A & K2)) -> (A & (K1 | K2)) == (K1 | K2) if K1 and K2 are a 1-bit mask

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Summary: This is the demorganed version of the case we already handle for the OR of iszero.

Reviewers: spatel

Reviewed By: spatel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34244

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305548 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Craig Topper 2017-06-16 05:10:37 +00:00
parent 9a18969a66
commit 091e96c54f
3 changed files with 69 additions and 44 deletions
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89
lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
View File

@ -763,8 +763,54 @@ foldAndOrOfEqualityCmpsWithConstants(ICmpInst *LHS, ICmpInst *RHS,
return nullptr;
}
// Fold (iszero(A & K1) | iszero(A & K2)) -> (A & (K1 | K2)) != (K1 | K2)
// Fold (!iszero(A & K1) & !iszero(A & K2)) -> (A & (K1 | K2)) == (K1 | K2)
Value *InstCombiner::foldAndOrOfICmpsOfAndWithPow2(ICmpInst *LHS, ICmpInst *RHS,
bool JoinedByAnd,
Instruction &CxtI) {
ICmpInst::Predicate Pred = LHS->getPredicate();
if (Pred != RHS->getPredicate())
return nullptr;
if (JoinedByAnd && Pred != ICmpInst::ICMP_NE)
return nullptr;
if (!JoinedByAnd && Pred != ICmpInst::ICMP_EQ)
return nullptr;
// TODO support vector splats
ConstantInt *LHSC = dyn_cast<ConstantInt>(LHS->getOperand(1));
ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS->getOperand(1));
if (!LHSC || !RHSC || !LHSC->isZero() || !RHSC->isZero())
return nullptr;
Value *A, *B, *C, *D;
if (match(LHS->getOperand(0), m_And(m_Value(A), m_Value(B))) &&
match(RHS->getOperand(0), m_And(m_Value(C), m_Value(D)))) {
if (A == D || B == D)
std::swap(C, D);
if (B == C)
std::swap(A, B);
if (A == C &&
isKnownToBeAPowerOfTwo(B, false, 0, &CxtI) &&
isKnownToBeAPowerOfTwo(D, false, 0, &CxtI)) {
Value *Mask = Builder->CreateOr(B, D);
Value *Masked = Builder->CreateAnd(A, Mask);
auto NewPred = JoinedByAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE;
return Builder->CreateICmp(NewPred, Masked, Mask);
}
}
return nullptr;
}
/// Fold (icmp)&(icmp) if possible.
Value *InstCombiner::foldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
Value *InstCombiner::foldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS,
Instruction &CxtI) {
// Fold (!iszero(A & K1) & !iszero(A & K2)) -> (A & (K1 | K2)) == (K1 | K2)
// if K1 and K2 are a one-bit mask.
if (Value *V = foldAndOrOfICmpsOfAndWithPow2(LHS, RHS, true, CxtI))
return V;
ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
// (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
@ -1127,7 +1173,7 @@ Instruction *InstCombiner::foldCastedBitwiseLogic(BinaryOperator &I) {
ICmpInst *ICmp0 = dyn_cast<ICmpInst>(Cast0Src);
ICmpInst *ICmp1 = dyn_cast<ICmpInst>(Cast1Src);
if (ICmp0 && ICmp1) {
Value *Res = LogicOpc == Instruction::And ? foldAndOfICmps(ICmp0, ICmp1)
Value *Res = LogicOpc == Instruction::And ? foldAndOfICmps(ICmp0, ICmp1, I)
: foldOrOfICmps(ICmp0, ICmp1, I);
if (Res)
return CastInst::Create(CastOpcode, Res, DestTy);
@ -1426,7 +1472,7 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
ICmpInst *LHS = dyn_cast<ICmpInst>(Op0);
ICmpInst *RHS = dyn_cast<ICmpInst>(Op1);
if (LHS && RHS)
if (Value *Res = foldAndOfICmps(LHS, RHS))
if (Value *Res = foldAndOfICmps(LHS, RHS, I))
return replaceInstUsesWith(I, Res);
// TODO: Make this recursive; it's a little tricky because an arbitrary
@ -1434,18 +1480,18 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
Value *X, *Y;
if (LHS && match(Op1, m_OneUse(m_And(m_Value(X), m_Value(Y))))) {
if (auto *Cmp = dyn_cast<ICmpInst>(X))
if (Value *Res = foldAndOfICmps(LHS, Cmp))
if (Value *Res = foldAndOfICmps(LHS, Cmp, I))
return replaceInstUsesWith(I, Builder->CreateAnd(Res, Y));
if (auto *Cmp = dyn_cast<ICmpInst>(Y))
if (Value *Res = foldAndOfICmps(LHS, Cmp))
if (Value *Res = foldAndOfICmps(LHS, Cmp, I))
return replaceInstUsesWith(I, Builder->CreateAnd(Res, X));
}
if (RHS && match(Op0, m_OneUse(m_And(m_Value(X), m_Value(Y))))) {
if (auto *Cmp = dyn_cast<ICmpInst>(X))
if (Value *Res = foldAndOfICmps(Cmp, RHS))
if (Value *Res = foldAndOfICmps(Cmp, RHS, I))
return replaceInstUsesWith(I, Builder->CreateAnd(Res, Y));
if (auto *Cmp = dyn_cast<ICmpInst>(Y))
if (Value *Res = foldAndOfICmps(Cmp, RHS))
if (Value *Res = foldAndOfICmps(Cmp, RHS, I))
return replaceInstUsesWith(I, Builder->CreateAnd(Res, X));
}
}
@ -1592,35 +1638,16 @@ static Value *matchSelectFromAndOr(Value *A, Value *C, Value *B, Value *D,
/// Fold (icmp)|(icmp) if possible.
Value *InstCombiner::foldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
Instruction &CxtI) {
ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
// Fold (iszero(A & K1) | iszero(A & K2)) -> (A & (K1 | K2)) != (K1 | K2)
// if K1 and K2 are a one-bit mask.
if (Value *V = foldAndOrOfICmpsOfAndWithPow2(LHS, RHS, false, CxtI))
return V;
ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
ConstantInt *LHSC = dyn_cast<ConstantInt>(LHS->getOperand(1));
ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS->getOperand(1));
// TODO support vector splats
if (LHS->getPredicate() == ICmpInst::ICMP_EQ && LHSC && LHSC->isZero() &&
RHS->getPredicate() == ICmpInst::ICMP_EQ && RHSC && RHSC->isZero()) {
Value *A, *B, *C, *D;
if (match(LHS->getOperand(0), m_And(m_Value(A), m_Value(B))) &&
match(RHS->getOperand(0), m_And(m_Value(C), m_Value(D)))) {
if (A == D || B == D)
std::swap(C, D);
if (B == C)
std::swap(A, B);
if (A == C &&
isKnownToBeAPowerOfTwo(B, false, 0, &CxtI) &&
isKnownToBeAPowerOfTwo(D, false, 0, &CxtI)) {
Value *Mask = Builder->CreateOr(B, D);
Value *Masked = Builder->CreateAnd(A, Mask);
return Builder->CreateICmp(ICmpInst::ICMP_NE, Masked, Mask);
}
}
}
// Fold (icmp ult/ule (A + C1), C3) | (icmp ult/ule (A + C2), C3)
// --> (icmp ult/ule ((A & ~(C1 ^ C2)) + max(C1, C2)), C3)
// The original condition actually refers to the following two ranges:

4
lib/Transforms/InstCombine/InstCombineInternal.h
View File

@ -447,12 +447,14 @@ private:
Instruction::CastOps isEliminableCastPair(const CastInst *CI1,
const CastInst *CI2);
Value *foldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS);
Value *foldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS, Instruction &CxtI);
Value *foldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS);
Value *foldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS, Instruction &CxtI);
Value *foldOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS);
Value *foldXorOfICmps(ICmpInst *LHS, ICmpInst *RHS);
Value *foldAndOrOfICmpsOfAndWithPow2(ICmpInst *LHS, ICmpInst *RHS,
bool JoinedByAnd, Instruction &CxtI);
public:
/// \brief Inserts an instruction \p New before instruction \p Old
///

20
test/Transforms/InstCombine/onehot_merge.ll
View File

@ -73,12 +73,10 @@ define i1 @foo1_or(i32 %k, i32 %c1, i32 %c2) {
; CHECK-LABEL: @foo1_or(
; CHECK-NEXT: [[TMP:%.*]] = shl i32 1, [[C1:%.*]]
; CHECK-NEXT: [[TMP4:%.*]] = lshr i32 -2147483648, [[C2:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[TMP]], [[K:%.*]]
; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i32 [[TMP1]], 0
; CHECK-NEXT: [[TMP5:%.*]] = and i32 [[TMP4]], [[K]]
; CHECK-NEXT: [[TMP6:%.*]] = icmp ne i32 [[TMP5]], 0
; CHECK-NEXT: [[OR:%.*]] = and i1 [[TMP2]], [[TMP6]]
; CHECK-NEXT: ret i1 [[OR]]
; CHECK-NEXT: [[TMP1:%.*]] = or i32 [[TMP]], [[TMP4]]
; CHECK-NEXT: [[TMP2:%.*]] = and i32 [[TMP1]], [[K:%.*]]
; CHECK-NEXT: [[TMP3:%.*]] = icmp eq i32 [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret i1 [[TMP3]]
;
%tmp = shl i32 1, %c1
%tmp4 = lshr i32 -2147483648, %c2
@ -96,12 +94,10 @@ define i1 @foo1_or_commuted(i32 %k, i32 %c1, i32 %c2) {
; CHECK-NEXT: [[K2:%.*]] = mul i32 [[K:%.*]], [[K]]
; CHECK-NEXT: [[TMP:%.*]] = shl i32 1, [[C1:%.*]]
; CHECK-NEXT: [[TMP4:%.*]] = lshr i32 -2147483648, [[C2:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[K2]], [[TMP]]
; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i32 [[TMP1]], 0
; CHECK-NEXT: [[TMP5:%.*]] = and i32 [[TMP4]], [[K2]]
; CHECK-NEXT: [[TMP6:%.*]] = icmp ne i32 [[TMP5]], 0
; CHECK-NEXT: [[OR:%.*]] = and i1 [[TMP2]], [[TMP6]]
; CHECK-NEXT: ret i1 [[OR]]
; CHECK-NEXT: [[TMP1:%.*]] = or i32 [[TMP]], [[TMP4]]
; CHECK-NEXT: [[TMP2:%.*]] = and i32 [[K2]], [[TMP1]]
; CHECK-NEXT: [[TMP3:%.*]] = icmp eq i32 [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret i1 [[TMP3]]
;
%k2 = mul i32 %k, %k ; to trick the complexity sorting
%tmp = shl i32 1, %c1