summaryrefslogtreecommitdiffstats
path: root/llvm/lib/Analysis/ValueTracking.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'llvm/lib/Analysis/ValueTracking.cpp')
-rw-r--r--llvm/lib/Analysis/ValueTracking.cpp110
1 files changed, 68 insertions, 42 deletions
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index b5e8a1d22f26..5ad4da43bca7 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -648,6 +648,7 @@ static void computeKnownBitsFromCmp(const Value *V, CmpInst::Predicate Pred,
auto m_V =
m_CombineOr(m_Specific(V), m_PtrToIntSameSize(Q.DL, m_Specific(V)));
+ Value *Y;
const APInt *Mask, *C;
uint64_t ShAmt;
switch (Pred) {
@@ -656,16 +657,18 @@ static void computeKnownBitsFromCmp(const Value *V, CmpInst::Predicate Pred,
if (match(LHS, m_V) && match(RHS, m_APInt(C))) {
Known = Known.unionWith(KnownBits::makeConstant(*C));
// assume(V & Mask = C)
- } else if (match(LHS, m_And(m_V, m_APInt(Mask))) &&
+ } else if (match(LHS, m_c_And(m_V, m_Value(Y))) &&
match(RHS, m_APInt(C))) {
// For one bits in Mask, we can propagate bits from C to V.
- Known.Zero |= ~*C & *Mask;
- Known.One |= *C & *Mask;
+ Known.One |= *C;
+ if (match(Y, m_APInt(Mask)))
+ Known.Zero |= ~*C & *Mask;
// assume(V | Mask = C)
- } else if (match(LHS, m_Or(m_V, m_APInt(Mask))) && match(RHS, m_APInt(C))) {
+ } else if (match(LHS, m_c_Or(m_V, m_Value(Y))) && match(RHS, m_APInt(C))) {
// For zero bits in Mask, we can propagate bits from C to V.
- Known.Zero |= ~*C & ~*Mask;
- Known.One |= *C & ~*Mask;
+ Known.Zero |= ~*C;
+ if (match(Y, m_APInt(Mask)))
+ Known.One |= *C & ~*Mask;
// assume(V ^ Mask = C)
} else if (match(LHS, m_Xor(m_V, m_APInt(Mask))) &&
match(RHS, m_APInt(C))) {
@@ -8390,8 +8393,7 @@ bool llvm::matchSimpleRecurrence(const BinaryOperator *I, PHINode *&P,
/// Return true if "icmp Pred LHS RHS" is always true.
static bool isTruePredicate(CmpInst::Predicate Pred, const Value *LHS,
- const Value *RHS, const DataLayout &DL,
- unsigned Depth) {
+ const Value *RHS) {
if (ICmpInst::isTrueWhenEqual(Pred) && LHS == RHS)
return true;
@@ -8403,8 +8405,26 @@ static bool isTruePredicate(CmpInst::Predicate Pred, const Value *LHS,
const APInt *C;
// LHS s<= LHS +_{nsw} C if C >= 0
- if (match(RHS, m_NSWAdd(m_Specific(LHS), m_APInt(C))))
+ // LHS s<= LHS | C if C >= 0
+ if (match(RHS, m_NSWAdd(m_Specific(LHS), m_APInt(C))) ||
+ match(RHS, m_Or(m_Specific(LHS), m_APInt(C))))
return !C->isNegative();
+
+ // LHS s<= smax(LHS, V) for any V
+ if (match(RHS, m_c_SMax(m_Specific(LHS), m_Value())))
+ return true;
+
+ // smin(RHS, V) s<= RHS for any V
+ if (match(LHS, m_c_SMin(m_Specific(RHS), m_Value())))
+ return true;
+
+ // Match A to (X +_{nsw} CA) and B to (X +_{nsw} CB)
+ const Value *X;
+ const APInt *CLHS, *CRHS;
+ if (match(LHS, m_NSWAddLike(m_Value(X), m_APInt(CLHS))) &&
+ match(RHS, m_NSWAddLike(m_Specific(X), m_APInt(CRHS))))
+ return CLHS->sle(*CRHS);
+
return false;
}
@@ -8414,34 +8434,36 @@ static bool isTruePredicate(CmpInst::Predicate Pred, const Value *LHS,
cast<OverflowingBinaryOperator>(RHS)->hasNoUnsignedWrap())
return true;
+ // LHS u<= LHS | V for any V
+ if (match(RHS, m_c_Or(m_Specific(LHS), m_Value())))
+ return true;
+
+ // LHS u<= umax(LHS, V) for any V
+ if (match(RHS, m_c_UMax(m_Specific(LHS), m_Value())))
+ return true;
+
// RHS >> V u<= RHS for any V
if (match(LHS, m_LShr(m_Specific(RHS), m_Value())))
return true;
- // Match A to (X +_{nuw} CA) and B to (X +_{nuw} CB)
- auto MatchNUWAddsToSameValue = [&](const Value *A, const Value *B,
- const Value *&X,
- const APInt *&CA, const APInt *&CB) {
- if (match(A, m_NUWAdd(m_Value(X), m_APInt(CA))) &&
- match(B, m_NUWAdd(m_Specific(X), m_APInt(CB))))
- return true;
+ // RHS u/ C_ugt_1 u<= RHS
+ const APInt *C;
+ if (match(LHS, m_UDiv(m_Specific(RHS), m_APInt(C))) && C->ugt(1))
+ return true;
- // If X & C == 0 then (X | C) == X +_{nuw} C
- if (match(A, m_Or(m_Value(X), m_APInt(CA))) &&
- match(B, m_Or(m_Specific(X), m_APInt(CB)))) {
- KnownBits Known(CA->getBitWidth());
- computeKnownBits(X, Known, DL, Depth + 1, /*AC*/ nullptr,
- /*CxtI*/ nullptr, /*DT*/ nullptr);
- if (CA->isSubsetOf(Known.Zero) && CB->isSubsetOf(Known.Zero))
- return true;
- }
+ // RHS & V u<= RHS for any V
+ if (match(LHS, m_c_And(m_Specific(RHS), m_Value())))
+ return true;
- return false;
- };
+ // umin(RHS, V) u<= RHS for any V
+ if (match(LHS, m_c_UMin(m_Specific(RHS), m_Value())))
+ return true;
+ // Match A to (X +_{nuw} CA) and B to (X +_{nuw} CB)
const Value *X;
const APInt *CLHS, *CRHS;
- if (MatchNUWAddsToSameValue(LHS, RHS, X, CLHS, CRHS))
+ if (match(LHS, m_NUWAddLike(m_Value(X), m_APInt(CLHS))) &&
+ match(RHS, m_NUWAddLike(m_Specific(X), m_APInt(CRHS))))
return CLHS->ule(*CRHS);
return false;
@@ -8453,37 +8475,36 @@ static bool isTruePredicate(CmpInst::Predicate Pred, const Value *LHS,
/// ALHS ARHS" is true. Otherwise, return std::nullopt.
static std::optional<bool>
isImpliedCondOperands(CmpInst::Predicate Pred, const Value *ALHS,
- const Value *ARHS, const Value *BLHS, const Value *BRHS,
- const DataLayout &DL, unsigned Depth) {
+ const Value *ARHS, const Value *BLHS, const Value *BRHS) {
switch (Pred) {
default:
return std::nullopt;
case CmpInst::ICMP_SLT:
case CmpInst::ICMP_SLE:
- if (isTruePredicate(CmpInst::ICMP_SLE, BLHS, ALHS, DL, Depth) &&
- isTruePredicate(CmpInst::ICMP_SLE, ARHS, BRHS, DL, Depth))
+ if (isTruePredicate(CmpInst::ICMP_SLE, BLHS, ALHS) &&
+ isTruePredicate(CmpInst::ICMP_SLE, ARHS, BRHS))
return true;
return std::nullopt;
case CmpInst::ICMP_SGT:
case CmpInst::ICMP_SGE:
- if (isTruePredicate(CmpInst::ICMP_SLE, ALHS, BLHS, DL, Depth) &&
- isTruePredicate(CmpInst::ICMP_SLE, BRHS, ARHS, DL, Depth))
+ if (isTruePredicate(CmpInst::ICMP_SLE, ALHS, BLHS) &&
+ isTruePredicate(CmpInst::ICMP_SLE, BRHS, ARHS))
return true;
return std::nullopt;
case CmpInst::ICMP_ULT:
case CmpInst::ICMP_ULE:
- if (isTruePredicate(CmpInst::ICMP_ULE, BLHS, ALHS, DL, Depth) &&
- isTruePredicate(CmpInst::ICMP_ULE, ARHS, BRHS, DL, Depth))
+ if (isTruePredicate(CmpInst::ICMP_ULE, BLHS, ALHS) &&
+ isTruePredicate(CmpInst::ICMP_ULE, ARHS, BRHS))
return true;
return std::nullopt;
case CmpInst::ICMP_UGT:
case CmpInst::ICMP_UGE:
- if (isTruePredicate(CmpInst::ICMP_ULE, ALHS, BLHS, DL, Depth) &&
- isTruePredicate(CmpInst::ICMP_ULE, BRHS, ARHS, DL, Depth))
+ if (isTruePredicate(CmpInst::ICMP_ULE, ALHS, BLHS) &&
+ isTruePredicate(CmpInst::ICMP_ULE, BRHS, ARHS))
return true;
return std::nullopt;
}
@@ -8527,7 +8548,7 @@ static std::optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
CmpInst::Predicate RPred,
const Value *R0, const Value *R1,
const DataLayout &DL,
- bool LHSIsTrue, unsigned Depth) {
+ bool LHSIsTrue) {
Value *L0 = LHS->getOperand(0);
Value *L1 = LHS->getOperand(1);
@@ -8574,7 +8595,7 @@ static std::optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
return LPred == RPred;
if (LPred == RPred)
- return isImpliedCondOperands(LPred, L0, L1, R0, R1, DL, Depth);
+ return isImpliedCondOperands(LPred, L0, L1, R0, R1);
return std::nullopt;
}
@@ -8636,8 +8657,7 @@ llvm::isImpliedCondition(const Value *LHS, CmpInst::Predicate RHSPred,
// Both LHS and RHS are icmps.
const ICmpInst *LHSCmp = dyn_cast<ICmpInst>(LHS);
if (LHSCmp)
- return isImpliedCondICmps(LHSCmp, RHSPred, RHSOp0, RHSOp1, DL, LHSIsTrue,
- Depth);
+ return isImpliedCondICmps(LHSCmp, RHSPred, RHSOp0, RHSOp1, DL, LHSIsTrue);
/// The LHS should be an 'or', 'and', or a 'select' instruction. We expect
/// the RHS to be an icmp.
@@ -9276,11 +9296,17 @@ void llvm::findValuesAffectedByCondition(
if (ICmpInst::isEquality(Pred)) {
if (match(B, m_ConstantInt())) {
+ Value *Y;
// (X & C) or (X | C) or (X ^ C).
// (X << C) or (X >>_s C) or (X >>_u C).
if (match(A, m_BitwiseLogic(m_Value(X), m_ConstantInt())) ||
match(A, m_Shift(m_Value(X), m_ConstantInt())))
AddAffected(X);
+ else if (match(A, m_And(m_Value(X), m_Value(Y))) ||
+ match(A, m_Or(m_Value(X), m_Value(Y)))) {
+ AddAffected(X);
+ AddAffected(Y);
+ }
}
} else {
// Handle (A + C1) u< C2, which is the canonical form of
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-08 16:28:49 +0000