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[Analysis] Unify most of the tracking between AssumptionCache and DomConditionCache
This helps cover some missing cases in both and hopefully serves as creating an easier framework for extending general condition based analysis. Closes #83161
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3 files changed

+63
-59
lines changed

3 files changed

+63
-59
lines changed

llvm/lib/Analysis/ValueTracking.cpp

Lines changed: 60 additions & 55 deletions
Original file line numberDiff line numberDiff line change
@@ -9124,6 +9124,14 @@ void llvm::findValuesAffectedByCondition(
91249124
addValueAffectedByCondition(V, InsertAffected);
91259125
};
91269126

9127+
auto AddCmpOperands = [&AddAffected, IsAssume](Value *LHS, Value *RHS) {
9128+
if (IsAssume) {
9129+
AddAffected(LHS);
9130+
AddAffected(RHS);
9131+
} else if (match(RHS, m_Constant()))
9132+
AddAffected(LHS);
9133+
};
9134+
91279135
SmallVector<Value *, 8> Worklist;
91289136
SmallPtrSet<Value *, 8> Visited;
91299137
Worklist.push_back(Cond);
@@ -9135,65 +9143,62 @@ void llvm::findValuesAffectedByCondition(
91359143
CmpInst::Predicate Pred;
91369144
Value *A, *B, *X;
91379145

9138-
if (IsAssume)
9146+
if (IsAssume) {
91399147
AddAffected(V);
9148+
if (match(V, m_Not(m_Value(X))))
9149+
AddAffected(X);
9150+
}
9151+
9152+
if (match(V, m_LogicalOp(m_Value(A), m_Value(B)))) {
9153+
// assume(A && B) is split to -> assume(A); assume(B);
9154+
// assume(!(A || B)) is split to -> assume(!A); assume(!B);
9155+
// Finally, assume(A || B) / assume(!(A && B)) generally don't provide
9156+
// enough information to be worth handling (intersection of information as
9157+
// opposed to union).
9158+
if (!IsAssume) {
9159+
Worklist.push_back(A);
9160+
Worklist.push_back(B);
9161+
}
9162+
} else if (match(V, m_ICmp(Pred, m_Value(A), m_Value(B)))) {
9163+
AddCmpOperands(A, B);
9164+
9165+
if (ICmpInst::isEquality(Pred)) {
9166+
if (match(B, m_ConstantInt())) {
9167+
// (X & C) or (X | C) or (X ^ C).
9168+
// (X << C) or (X >>_s C) or (X >>_u C).
9169+
if (match(A, m_BitwiseLogic(m_Value(X), m_ConstantInt())) ||
9170+
match(A, m_Shift(m_Value(X), m_ConstantInt())))
9171+
AddAffected(X);
9172+
}
9173+
} else {
9174+
// Handle (A + C1) u< C2, which is the canonical form of
9175+
// A > C3 && A < C4.
9176+
if (match(A, m_Add(m_Value(X), m_ConstantInt())) &&
9177+
match(B, m_ConstantInt()))
9178+
AddAffected(X);
9179+
9180+
// Handle icmp slt/sgt (bitcast X to int), 0/-1, which is supported
9181+
// by computeKnownFPClass().
9182+
if (match(A, m_ElementWiseBitCast(m_Value(X)))) {
9183+
if (Pred == ICmpInst::ICMP_SLT && match(B, m_Zero()))
9184+
InsertAffected(X);
9185+
else if (Pred == ICmpInst::ICMP_SGT && match(B, m_AllOnes()))
9186+
InsertAffected(X);
9187+
}
9188+
}
9189+
} else if (match(Cond, m_FCmp(Pred, m_Value(A), m_Value(B)))) {
9190+
AddCmpOperands(A, B);
91409191

9141-
if (IsAssume && match(V, m_Not(m_Value(X))))
9142-
AddAffected(X);
9143-
if (!IsAssume && match(V, m_LogicalOp(m_Value(A), m_Value(B)))) {
9144-
Worklist.push_back(A);
9145-
Worklist.push_back(B);
9146-
} else if (match(V, m_Cmp(Pred, m_Value(A), m_Value(B))) &&
9147-
(IsAssume || isa<ICmpInst>(V))) {
9148-
if (IsAssume || match(B, m_Constant())) {
9192+
// fcmp fneg(x), y
9193+
// fcmp fabs(x), y
9194+
// fcmp fneg(fabs(x)), y
9195+
if (match(A, m_FNeg(m_Value(A))))
9196+
AddAffected(A);
9197+
if (match(A, m_FAbs(m_Value(A))))
91499198
AddAffected(A);
9150-
if (IsAssume)
9151-
AddAffected(B);
9152-
9153-
if (IsAssume ? (Pred == ICmpInst::ICMP_EQ)
9154-
: ICmpInst::isEquality(Pred)) {
9155-
if (match(B, m_ConstantInt())) {
9156-
// (X & C) or (X | C) or (X ^ C).
9157-
// (X << C) or (X >>_s C) or (X >>_u C).
9158-
if (match(A, m_BitwiseLogic(m_Value(X), m_ConstantInt())) ||
9159-
match(A, m_Shift(m_Value(X), m_ConstantInt())))
9160-
AddAffected(X);
9161-
}
9162-
} else {
9163-
if (Pred == ICmpInst::ICMP_NE)
9164-
if (match(A, m_And(m_Value(X), m_Power2())) && match(B, m_Zero()))
9165-
AddAffected(X);
9166-
9167-
if (!IsAssume || Pred == ICmpInst::ICMP_ULT) {
9168-
// Handle (A + C1) u< C2, which is the canonical form of
9169-
// A > C3 && A < C4.
9170-
if (match(A, m_Add(m_Value(X), m_ConstantInt())) &&
9171-
match(B, m_ConstantInt()))
9172-
AddAffected(X);
9173-
}
9174-
if (!IsAssume) {
9175-
// Handle icmp slt/sgt (bitcast X to int), 0/-1, which is supported
9176-
// by computeKnownFPClass().
9177-
if ((Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SGT) &&
9178-
match(A, m_ElementWiseBitCast(m_Value(X))))
9179-
InsertAffected(X);
9180-
}
91819199

9182-
if (IsAssume && CmpInst::isFPPredicate(Pred)) {
9183-
// fcmp fneg(x), y
9184-
// fcmp fabs(x), y
9185-
// fcmp fneg(fabs(x)), y
9186-
if (match(A, m_FNeg(m_Value(A))))
9187-
AddAffected(A);
9188-
if (match(A, m_FAbs(m_Value(A))))
9189-
AddAffected(A);
9190-
}
9191-
}
9192-
}
9193-
} else if ((!IsAssume &&
9194-
match(Cond, m_FCmp(Pred, m_Value(A), m_Constant()))) ||
9195-
match(Cond, m_Intrinsic<Intrinsic::is_fpclass>(m_Value(A),
9196-
m_Value(B)))) {
9200+
} else if (match(V, m_Intrinsic<Intrinsic::is_fpclass>(m_Value(A),
9201+
m_Value()))) {
91979202
// Handle patterns that computeKnownFPClass() support.
91989203
AddAffected(A);
91999204
}

llvm/test/Analysis/ValueTracking/numsignbits-from-assume.ll

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -51,7 +51,7 @@ define i32 @computeNumSignBits_sub1(i32 %in) {
5151

5252
define i32 @computeNumSignBits_sub2(i32 %in) {
5353
; CHECK-LABEL: @computeNumSignBits_sub2(
54-
; CHECK-NEXT: [[SUB:%.*]] = add i32 [[IN:%.*]], -1
54+
; CHECK-NEXT: [[SUB:%.*]] = add nsw i32 [[IN:%.*]], -1
5555
; CHECK-NEXT: [[COND:%.*]] = icmp ult i32 [[SUB]], 43
5656
; CHECK-NEXT: call void @llvm.assume(i1 [[COND]])
5757
; CHECK-NEXT: [[SH:%.*]] = shl nuw nsw i32 [[SUB]], 3

llvm/test/Transforms/InstCombine/fpclass-from-dom-cond.ll

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -185,10 +185,9 @@ define i1 @test8(float %x) {
185185
; CHECK-NEXT: [[COND:%.*]] = fcmp oeq float [[ABS]], 0x7FF0000000000000
186186
; CHECK-NEXT: br i1 [[COND]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
187187
; CHECK: if.then:
188-
; CHECK-NEXT: [[RET1:%.*]] = call i1 @llvm.is.fpclass.f32(float [[X]], i32 575)
189-
; CHECK-NEXT: ret i1 [[RET1]]
188+
; CHECK-NEXT: ret i1 true
190189
; CHECK: if.else:
191-
; CHECK-NEXT: [[RET2:%.*]] = call i1 @llvm.is.fpclass.f32(float [[X]], i32 575)
190+
; CHECK-NEXT: [[RET2:%.*]] = call i1 @llvm.is.fpclass.f32(float [[X]], i32 59)
192191
; CHECK-NEXT: ret i1 [[RET2]]
193192
;
194193
%abs = call float @llvm.fabs.f32(float %x)

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