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[ConstraintElim] Refactor checkCondition. NFC. #75319

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Merged
merged 1 commit into from
Dec 13, 2023
Merged

[ConstraintElim] Refactor checkCondition. NFC. #75319

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61 changes: 31 additions & 30 deletions llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1109,6 +1109,14 @@ void State::addInfoFor(BasicBlock &BB) {
CmpI->getOperand(1)));
}

static void dumpUnpackedICmp(raw_ostream &OS, ICmpInst::Predicate Pred,
Value *LHS, Value *RHS) {
OS << "icmp " << Pred << ' ';
LHS->printAsOperand(OS, /*PrintType=*/true);
OS << ", ";
RHS->printAsOperand(OS, /*PrintType=*/false);
}

namespace {
/// Helper to keep track of a condition and if it should be treated as negated
/// for reproducer construction.
Expand Down Expand Up @@ -1241,10 +1249,9 @@ static void generateReproducer(CmpInst *Cond, Module *M,
if (Entry.Pred == ICmpInst::BAD_ICMP_PREDICATE)
continue;

LLVM_DEBUG(
dbgs() << " Materializing assumption icmp " << Entry.Pred << ' ';
Entry.LHS->printAsOperand(dbgs(), /*PrintType=*/true); dbgs() << ", ";
Entry.RHS->printAsOperand(dbgs(), /*PrintType=*/false); dbgs() << "\n");
LLVM_DEBUG(dbgs() << " Materializing assumption ";
dumpUnpackedICmp(dbgs(), Entry.Pred, Entry.LHS, Entry.RHS);
dbgs() << "\n");
CloneInstructions({Entry.LHS, Entry.RHS}, CmpInst::isSigned(Entry.Pred));

auto *Cmp = Builder.CreateICmp(Entry.Pred, Entry.LHS, Entry.RHS);
Expand All @@ -1260,14 +1267,12 @@ static void generateReproducer(CmpInst *Cond, Module *M,
assert(!verifyFunction(*F, &dbgs()));
}

static std::optional<bool> checkCondition(CmpInst *Cmp, ConstraintInfo &Info,
unsigned NumIn, unsigned NumOut,
static std::optional<bool> checkCondition(CmpInst::Predicate Pred, Value *A,
Value *B, Instruction *CheckInst,
ConstraintInfo &Info, unsigned NumIn,
unsigned NumOut,
Instruction *ContextInst) {
LLVM_DEBUG(dbgs() << "Checking " << *Cmp << "\n");

CmpInst::Predicate Pred = Cmp->getPredicate();
Value *A = Cmp->getOperand(0);
Value *B = Cmp->getOperand(1);
LLVM_DEBUG(dbgs() << "Checking " << *CheckInst << "\n");

auto R = Info.getConstraintForSolving(Pred, A, B);
if (R.empty() || !R.isValid(Info)){
Expand All @@ -1292,13 +1297,10 @@ static std::optional<bool> checkCondition(CmpInst *Cmp, ConstraintInfo &Info,
return std::nullopt;

LLVM_DEBUG({
if (*ImpliedCondition) {
dbgs() << "Condition " << *Cmp;
} else {
auto InversePred = Cmp->getInversePredicate();
dbgs() << "Condition " << CmpInst::getPredicateName(InversePred) << " "
<< *A << ", " << *B;
}
dbgs() << "Condition ";
dumpUnpackedICmp(
dbgs(), *ImpliedCondition ? Pred : CmpInst::getInversePredicate(Pred),
A, B);
dbgs() << " implied by dominating constraints\n";
CSToUse.dump();
});
Expand Down Expand Up @@ -1338,8 +1340,9 @@ static bool checkAndReplaceCondition(
return true;
};

if (auto ImpliedCondition =
checkCondition(Cmp, Info, NumIn, NumOut, ContextInst))
if (auto ImpliedCondition = checkCondition(
Cmp->getPredicate(), Cmp->getOperand(0), Cmp->getOperand(1), Cmp,
Info, NumIn, NumOut, ContextInst))
return ReplaceCmpWithConstant(Cmp, *ImpliedCondition);
return false;
}
Expand Down Expand Up @@ -1380,9 +1383,10 @@ static bool checkAndSecondOpImpliedByFirst(

bool Changed = false;
// Check if the second condition can be simplified now.
if (auto ImpliedCondition =
checkCondition(cast<ICmpInst>(And->getOperand(1)), Info, CB.NumIn,
CB.NumOut, CB.getContextInst())) {
ICmpInst *Cmp = cast<ICmpInst>(And->getOperand(1));
if (auto ImpliedCondition = checkCondition(
Cmp->getPredicate(), Cmp->getOperand(0), Cmp->getOperand(1), Cmp,
Info, CB.NumIn, CB.NumOut, CB.getContextInst())) {
And->setOperand(1, ConstantInt::getBool(And->getType(), *ImpliedCondition));
Changed = true;
}
Expand All @@ -1408,9 +1412,8 @@ void ConstraintInfo::addFact(CmpInst::Predicate Pred, Value *A, Value *B,
if (!R.isValid(*this) || R.isNe())
return;

LLVM_DEBUG(dbgs() << "Adding '" << Pred << " ";
A->printAsOperand(dbgs(), false); dbgs() << ", ";
B->printAsOperand(dbgs(), false); dbgs() << "'\n");
LLVM_DEBUG(dbgs() << "Adding '"; dumpUnpackedICmp(dbgs(), Pred, A, B);
dbgs() << "'\n");
bool Added = false;
auto &CSToUse = getCS(R.IsSigned);
if (R.Coefficients.empty())
Expand Down Expand Up @@ -1616,10 +1619,8 @@ static bool eliminateConstraints(Function &F, DominatorTree &DT, LoopInfo &LI,
}

auto AddFact = [&](CmpInst::Predicate Pred, Value *A, Value *B) {
LLVM_DEBUG(dbgs() << "fact to add to the system: "
<< CmpInst::getPredicateName(Pred) << " ";
A->printAsOperand(dbgs()); dbgs() << ", ";
B->printAsOperand(dbgs(), false); dbgs() << "\n");
LLVM_DEBUG(dbgs() << "fact to add to the system: ";
dumpUnpackedICmp(dbgs(), Pred, A, B); dbgs() << "\n");
if (Info.getCS(CmpInst::isSigned(Pred)).size() > MaxRows) {
LLVM_DEBUG(
dbgs()
Expand Down
20 changes: 10 additions & 10 deletions llvm/test/Transforms/ConstraintElimination/debug.ll
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Expand Up @@ -3,16 +3,16 @@
; REQUIRES: asserts

define i1 @test_and_ule(i4 %x, i4 %y, i4 %z) {
; CHECK: Processing fact to add to the system: ule i4 %x, %y
; CHECK-NEXT: Adding 'ule %x, %y'
; CHECK: Processing fact to add to the system: icmp ule i4 %x, %y
; CHECK-NEXT: Adding 'icmp ule i4 %x, %y'
; CHECK-NEXT: constraint: %x + -1 * %y <= 0

; CHECK: Processing fact to add to the system: ule i4 %y, %z
; CHECK-NEXT: Adding 'ule %y, %z'
; CHECK: Processing fact to add to the system: icmp ule i4 %y, %z
; CHECK-NEXT: Adding 'icmp ule i4 %y, %z'
; CHECK-NEXT: constraint: %y + -1 * %z <= 0

; CHECK: Checking %t.1 = icmp ule i4 %x, %z
; CHECK: Condition %t.1 = icmp ule i4 %x, %z implied by dominating constraints
; CHECK: Condition icmp ule i4 %x, %z implied by dominating constraints

; CHECK: Removing %y + -1 * %z <= 0
; CHECK: Removing %x + -1 * %y <= 0
Expand All @@ -33,16 +33,16 @@ exit:
}

define i1 @test_and_ugt(i4 %x, i4 %y, i4 %z) {
; CHECK: Processing fact to add to the system: ugt i4 %x, %y
; CHECK-NEXT: Adding 'ugt %x, %y'
; CHECK: Processing fact to add to the system: icmp ugt i4 %x, %y
; CHECK-NEXT: Adding 'icmp ugt i4 %x, %y'
; CHECK-NEXT: constraint: -1 * %x + %y <= -1

; CHECK: Processing fact to add to the system: ugt i4 %y, %z
; CHECK-NEXT: Adding 'ugt %y, %z'
; CHECK: Processing fact to add to the system: icmp ugt i4 %y, %z
; CHECK-NEXT: Adding 'icmp ugt i4 %y, %z'
; CHECK-NEXT: constraint: -1 * %y + %z <= -1

; CHECK: Checking %f.1 = icmp ule i4 %x, %z
; CHECK: Condition ugt i4 %x, i4 %z implied by dominating constraints
; CHECK: Condition icmp ugt i4 %x, %z implied by dominating constraints

; CHECK: Removing -1 * %y + %z <= -1
; CHECK: Removing -1 * %x + %y <= -1
Expand Down
2 changes: 1 addition & 1 deletion llvm/test/Transforms/ConstraintElimination/reproducer-remarks-debug.ll
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Expand Up @@ -4,7 +4,7 @@

target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"

; CHECK: Condition %c.2 = icmp eq ptr %a, null implied by dominating constraints
; CHECK: Condition icmp eq ptr %a, null implied by dominating constraints
; CHECK-NEXT: %a <= 0
; CHECK-NEXT: Creating reproducer for %c.2 = icmp eq ptr %a, null
; CHECK-NEXT: found external input ptr %a
Expand Down