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[ValueTracking] Handle and/or of conditions in computeKnownFPClassFromContext #118257

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Merged
merged 3 commits into from
Dec 2, 2024
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[ValueTracking] Handle and/or of conditions in computeKnownFPClassFromContext #118257

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688bb43
[ValueTracking] Add pre-commit tests. NFC.
dtcxzyw Dec 2, 2024
07493fc
[ValueTracking] Handle and/or of conditions in `computeKnownFPClassFr…
dtcxzyw Dec 2, 2024
c7744a9
[ValueTracking] Add depth limit
dtcxzyw Dec 2, 2024
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26 changes: 18 additions & 8 deletions llvm/lib/Analysis/ValueTracking.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4882,9 +4882,19 @@ llvm::fcmpImpliesClass(CmpInst::Predicate Pred, const Function &F, Value *LHS,
}

static void computeKnownFPClassFromCond(const Value *V, Value *Cond,
bool CondIsTrue,
unsigned Depth, bool CondIsTrue,
const Instruction *CxtI,
KnownFPClass &KnownFromContext) {
Value *A, *B;
if (Depth < MaxAnalysisRecursionDepth &&
(CondIsTrue ? match(Cond, m_LogicalAnd(m_Value(A), m_Value(B)))
: match(Cond, m_LogicalOr(m_Value(A), m_Value(B))))) {
computeKnownFPClassFromCond(V, A, Depth + 1, CondIsTrue, CxtI,
KnownFromContext);
computeKnownFPClassFromCond(V, B, Depth + 1, CondIsTrue, CxtI,
KnownFromContext);
return;
}
CmpInst::Predicate Pred;
Value *LHS;
uint64_t ClassVal = 0;
Expand Down Expand Up @@ -4925,13 +4935,13 @@ static KnownFPClass computeKnownFPClassFromContext(const Value *V,

BasicBlockEdge Edge0(BI->getParent(), BI->getSuccessor(0));
if (Q.DT->dominates(Edge0, Q.CxtI->getParent()))
computeKnownFPClassFromCond(V, Cond, /*CondIsTrue=*/true, Q.CxtI,
KnownFromContext);
computeKnownFPClassFromCond(V, Cond, /*Depth=*/0, /*CondIsTrue=*/true,
Q.CxtI, KnownFromContext);

BasicBlockEdge Edge1(BI->getParent(), BI->getSuccessor(1));
if (Q.DT->dominates(Edge1, Q.CxtI->getParent()))
computeKnownFPClassFromCond(V, Cond, /*CondIsTrue=*/false, Q.CxtI,
KnownFromContext);
computeKnownFPClassFromCond(V, Cond, /*Depth=*/0, /*CondIsTrue=*/false,
Q.CxtI, KnownFromContext);
}
}

Expand All @@ -4953,8 +4963,8 @@ static KnownFPClass computeKnownFPClassFromContext(const Value *V,
if (!isValidAssumeForContext(I, Q.CxtI, Q.DT))
continue;

computeKnownFPClassFromCond(V, I->getArgOperand(0), /*CondIsTrue=*/true,
Q.CxtI, KnownFromContext);
computeKnownFPClassFromCond(V, I->getArgOperand(0), /*Depth=*/0,
/*CondIsTrue=*/true, Q.CxtI, KnownFromContext);
}

return KnownFromContext;
Expand Down Expand Up @@ -10090,7 +10100,7 @@ void llvm::findValuesAffectedByCondition(

if (HasRHSC && match(A, m_Intrinsic<Intrinsic::ctpop>(m_Value(X))))
AddAffected(X);
} else if (match(Cond, m_FCmp(Pred, m_Value(A), m_Value(B)))) {
} else if (match(V, m_FCmp(Pred, m_Value(A), m_Value(B)))) {
AddCmpOperands(A, B);

// fcmp fneg(x), y
Expand Down
32 changes: 27 additions & 5 deletions llvm/test/Transforms/InstCombine/fpclass-from-dom-cond.ll
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Expand Up @@ -46,6 +46,31 @@ if.end:
ret i1 %cmp.i
}

define i1 @test2_or(double %x, i1 %cond) {
; CHECK-LABEL: define i1 @test2_or(
; CHECK-SAME: double [[X:%.*]], i1 [[COND:%.*]]) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[CMP:%.*]] = fcmp olt double [[X]], 0x3EB0C6F7A0000000
; CHECK-NEXT: [[OR:%.*]] = or i1 [[CMP]], [[COND]]
; CHECK-NEXT: br i1 [[OR]], label [[IF_THEN:%.*]], label [[IF_END:%.*]]
; CHECK: if.then:
; CHECK-NEXT: ret i1 false
; CHECK: if.end:
; CHECK-NEXT: ret i1 false
;
entry:
%cmp = fcmp olt double %x, 0x3EB0C6F7A0000000
%or = or i1 %cmp, %cond
br i1 %or, label %if.then, label %if.end

if.then:
ret i1 false

if.end:
%cmp.i = fcmp oeq double %x, 0.000000e+00
ret i1 %cmp.i
}

define i1 @test3(float %x) {
; CHECK-LABEL: define i1 @test3(
; CHECK-SAME: float [[X:%.*]]) {
Expand Down Expand Up @@ -240,16 +265,14 @@ if.else:
ret i1 false
}

; TODO: handle and/or conditions
define i1 @test11_and(float %x, i1 %cond2) {
; CHECK-LABEL: define i1 @test11_and(
; CHECK-SAME: float [[X:%.*]], i1 [[COND2:%.*]]) {
; CHECK-NEXT: [[COND:%.*]] = fcmp olt float [[X]], -1.000000e+00
; CHECK-NEXT: [[AND:%.*]] = and i1 [[COND]], [[COND2]]
; CHECK-NEXT: br i1 [[AND]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
; CHECK: if.then:
; CHECK-NEXT: [[RET1:%.*]] = fcmp oeq float [[X]], 0x7FF0000000000000
; CHECK-NEXT: ret i1 [[RET1]]
; CHECK-NEXT: ret i1 false
; CHECK: if.else:
; CHECK-NEXT: ret i1 false
;
Expand All @@ -264,7 +287,6 @@ if.else:
ret i1 false
}

; TODO: handle and/or conditions
define i1 @test12_or(float %x, i1 %cond2) {
; CHECK-LABEL: define i1 @test12_or(
; CHECK-SAME: float [[X:%.*]], i1 [[COND2:%.*]]) {
Expand All @@ -275,7 +297,7 @@ define i1 @test12_or(float %x, i1 %cond2) {
; CHECK: if.then:
; CHECK-NEXT: ret i1 false
; CHECK: if.else:
; CHECK-NEXT: [[RET:%.*]] = call i1 @llvm.is.fpclass.f32(float [[X]], i32 783)
; CHECK-NEXT: [[RET:%.*]] = call i1 @llvm.is.fpclass.f32(float [[X]], i32 780)
; CHECK-NEXT: ret i1 [[RET]]
;
entry:
Expand Down