[Attributor] AAPotentialValues Interface

This is a split patch of D80991.
This patch introduces AAPotentialValues and its interface only.
For more detail of AAPotentialValues abstract attribute, see the original patch.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D83283

include/llvm/ADT/APInt.h

@@ -15,6 +15,7 @@
 #ifndef LLVM_ADT_APINT_H
 #define LLVM_ADT_APINT_H
 
+#include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/MathExtras.h"
 #include <cassert>
@@ -96,7 +97,7 @@ private:
 
   unsigned BitWidth; ///< The number of bits in this APInt.
 
-  friend struct DenseMapAPIntKeyInfo;
+  friend struct DenseMapInfo<APInt>;
 
   friend class APSInt;
 
@@ -2288,6 +2289,29 @@ void StoreIntToMemory(const APInt &IntVal, uint8_t *Dst, unsigned StoreBytes);
 /// from Src into IntVal, which is assumed to be wide enough and to hold zero.
 void LoadIntFromMemory(APInt &IntVal, const uint8_t *Src, unsigned LoadBytes);
 
+/// Provide DenseMapInfo for APInt.
+template <> struct DenseMapInfo<APInt> {
+  static inline APInt getEmptyKey() {
+    APInt V(nullptr, 0);
+    V.U.VAL = 0;
+    return V;
+  }
+
+  static inline APInt getTombstoneKey() {
+    APInt V(nullptr, 0);
+    V.U.VAL = 1;
+    return V;
+  }
+
+  static unsigned getHashValue(const APInt &Key) {
+    return static_cast<unsigned>(hash_value(Key));
+  }
+
+  static bool isEqual(const APInt &LHS, const APInt &RHS) {
+    return LHS.getBitWidth() == RHS.getBitWidth() && LHS == RHS;
+  }
+};
+
 } // namespace llvm
 
 #endif

include/llvm/Transforms/IPO/Attributor.h

@@ -97,6 +97,7 @@
 #ifndef LLVM_TRANSFORMS_IPO_ATTRIBUTOR_H
 #define LLVM_TRANSFORMS_IPO_ATTRIBUTOR_H
 
+#include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/GraphTraits.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/STLExtras.h"
@@ -115,6 +116,7 @@
 #include "llvm/IR/PassManager.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Casting.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/DOTGraphTraits.h"
 #include "llvm/Support/GraphWriter.h"
 #include "llvm/Support/TimeProfiler.h"
@@ -3348,6 +3350,191 @@ struct AAValueConstantRange
   static const char ID;
 };
 
+/// A class for a set state.
+/// The assumed boolean state indicates whether the corresponding set is full
+/// set or not. If the assumed state is false, this is the worst state. The
+/// worst state (invalid state) of set of potential values is when the set
+/// contains every possible value (i.e. we cannot in any way limit the value
+/// that the target position can take). That never happens naturally, we only
+/// force it. As for the conditions under which we force it, see
+/// AAPotentialValues.
+template <typename MemberTy, typename KeyInfo = DenseMapInfo<MemberTy>>
+struct PotentialValuesState : BooleanState {
+  using SetTy = DenseSet<MemberTy, KeyInfo>;
+
+  PotentialValuesState() : BooleanState(true) {}
+
+  PotentialValuesState(bool IsValid) : BooleanState(IsValid) {}
+
+  /// Return this set. We should check whether this set is valid or not by
+  /// isValidState() before calling this function.
+  const SetTy &getAssumedSet() const {
+    assert(isValidState() && "This set shoud not be used when it is invalid!");
+    return Set;
+  }
+
+  bool operator==(const PotentialValuesState &RHS) const {
+    if (isValidState() != RHS.isValidState())
+      return false;
+    if (!isValidState() && !RHS.isValidState())
+      return true;
+    return Set == RHS.getAssumedSet();
+  }
+
+  /// Maximum number of potential values to be tracked.
+  /// This is set by -attributor-max-potential-values command line option
+  static unsigned MaxPotentialValues;
+
+  /// Return empty set as the best state of potential values.
+  static PotentialValuesState getBestState() {
+    return PotentialValuesState(true);
+  }
+
+  static PotentialValuesState getBestState(PotentialValuesState &PVS) {
+    return getBestState();
+  }
+
+  /// Return full set as the worst state of potential values.
+  static PotentialValuesState getWorstState() {
+    return PotentialValuesState(false);
+  }
+
+  /// Union assumed set with the passed value.
+  void unionAssumed(const MemberTy &C) { insert(C); }
+
+  /// Union assumed set with assumed set of the passed state \p PVS.
+  void unionAssumed(const PotentialValuesState &PVS) { unionWith(PVS); }
+
+  /// "Clamp" this state with \p PVS.
+  PotentialValuesState operator^=(const PotentialValuesState &PVS) {
+    unionAssumed(PVS);
+    return *this;
+  }
+
+  PotentialValuesState operator&=(const PotentialValuesState &PVS) {
+    unionAssumed(PVS);
+    return *this;
+  }
+
+private:
+  /// Check the size of this set, and invalidate when the size is no
+  /// less than \p MaxPotentialValues threshold.
+  void checkAndInvalidate() {
+    if (Set.size() >= MaxPotentialValues)
+      indicatePessimisticFixpoint();
+  }
+
+  /// Insert an element into this set.
+  void insert(const MemberTy &C) {
+    if (!isValidState())
+      return;
+    Set.insert(C);
+    checkAndInvalidate();
+  }
+
+  /// Take union with R.
+  void unionWith(const PotentialValuesState &R) {
+    /// If this is a full set, do nothing.;
+    if (!isValidState())
+      return;
+    /// If R is full set, change L to a full set.
+    if (!R.isValidState()) {
+      indicatePessimisticFixpoint();
+      return;
+    }
+    for (const MemberTy &C : R.Set)
+      Set.insert(C);
+    checkAndInvalidate();
+  }
+
+  /// Take intersection with R.
+  void intersectWith(const PotentialValuesState &R) {
+    /// If R is a full set, do nothing.
+    if (!R.isValidState())
+      return;
+    /// If this is a full set, change this to R.
+    if (!isValidState()) {
+      *this = R;
+      return;
+    }
+    SetTy IntersectSet;
+    for (const MemberTy &C : Set) {
+      if (R.Set.count(C))
+        IntersectSet.insert(C);
+    }
+    Set = IntersectSet;
+  }
+
+  /// Container for potential values
+  SetTy Set;
+};
+
+using PotentialConstantIntValuesState = PotentialValuesState<APInt>;
+
+raw_ostream &operator<<(raw_ostream &OS,
+                        const PotentialConstantIntValuesState &R);
+
+/// An abstract interface for potential values analysis.
+///
+/// This AA collects potential values for each IR position.
+/// An assumed set of potential values is initialized with the empty set (the
+/// best state) and it will grow monotonically as we find more potential values
+/// for this position.
+/// The set might be forced to the worst state, that is, to contain every
+/// possible value for this position in 2 cases.
+///   1. We surpassed the \p MaxPotentialValues threshold. This includes the
+///      case that this position is affected (e.g. because of an operation) by a
+///      Value that is in the worst state.
+///   2. We tried to initialize on a Value that we cannot handle (e.g. an
+///      operator we do not currently handle).
+///
+/// TODO: Support values other than constant integers.
+struct AAPotentialValues
+    : public StateWrapper<PotentialConstantIntValuesState, AbstractAttribute> {
+  using Base = StateWrapper<PotentialConstantIntValuesState, AbstractAttribute>;
+  AAPotentialValues(const IRPosition &IRP, Attributor &A) : Base(IRP) {}
+
+  /// See AbstractAttribute::getState(...).
+  PotentialConstantIntValuesState &getState() override { return *this; }
+  const PotentialConstantIntValuesState &getState() const override {
+    return *this;
+  }
+
+  /// Create an abstract attribute view for the position \p IRP.
+  static AAPotentialValues &createForPosition(const IRPosition &IRP,
+                                              Attributor &A);
+
+  /// Return assumed constant for the associated value
+  Optional<ConstantInt *>
+  getAssumedConstantInt(Attributor &A,
+                        const Instruction *CtxI = nullptr) const {
+    if (!isValidState())
+      return nullptr;
+    if (getAssumedSet().size() == 1)
+      return cast<ConstantInt>(ConstantInt::get(getAssociatedValue().getType(),
+                                                *(getAssumedSet().begin())));
+    if (getAssumedSet().size() == 0)
+      return llvm::None;
+
+    return nullptr;
+  }
+
+  /// See AbstractAttribute::getName()
+  const std::string getName() const override { return "AAPotentialValues"; }
+
+  /// See AbstractAttribute::getIdAddr()
+  const char *getIdAddr() const override { return &ID; }
+
+  /// This function should return true if the type of the \p AA is
+  /// AAPotentialValues
+  static bool classof(const AbstractAttribute *AA) {
+    return (AA->getIdAddr() == &ID);
+  }
+
+  /// Unique ID (due to the unique address)
+  static const char ID;
+};
+
 /// Run options, used by the pass manager.
 enum AttributorRunOption {
   NONE = 0,

lib/IR/LLVMContextImpl.h

@@ -57,27 +57,7 @@ class Type;
 class Value;
 class ValueHandleBase;
 
-struct DenseMapAPIntKeyInfo {
-  static inline APInt getEmptyKey() {
-    APInt V(nullptr, 0);
-    V.U.VAL = 0;
-    return V;
-  }
-
-  static inline APInt getTombstoneKey() {
-    APInt V(nullptr, 0);
-    V.U.VAL = 1;
-    return V;
-  }
-
-  static unsigned getHashValue(const APInt &Key) {
-    return static_cast<unsigned>(hash_value(Key));
-  }
-
-  static bool isEqual(const APInt &LHS, const APInt &RHS) {
-    return LHS.getBitWidth() == RHS.getBitWidth() && LHS == RHS;
-  }
-};
+using DenseMapAPIntKeyInfo = DenseMapInfo<APInt>;
 
 struct DenseMapAPFloatKeyInfo {
   static inline APFloat getEmptyKey() { return APFloat(APFloat::Bogus(), 1); }

lib/Transforms/IPO/Attributor.cpp

@@ -2079,6 +2079,19 @@ raw_ostream &llvm::operator<<(raw_ostream &OS, const AbstractAttribute &AA) {
   return OS;
 }
 
+raw_ostream &llvm::operator<<(raw_ostream &OS,
+                              const PotentialConstantIntValuesState &S) {
+  OS << "set-state(< {";
+  if (!S.isValidState())
+    OS << "full-set";
+  else
+    for (auto &it : S.getAssumedSet())
+      OS << it << ", ";
+  OS << "} >)";
+
+  return OS;
+}
+
 void AbstractAttribute::print(raw_ostream &OS) const {
   OS << "[";
   OS << getName();

lib/Transforms/IPO/AttributorAttributes.cpp

@@ -45,6 +45,16 @@ static cl::opt<bool> ManifestInternal(
 static cl::opt<int> MaxHeapToStackSize("max-heap-to-stack-size", cl::init(128),
                                        cl::Hidden);
 
+static cl::opt<unsigned, true> MaxPotentialValues(
+    "attributor-max-potential-values", cl::Hidden,
+    cl::desc("Maximum number of potential values to be "
+             "tracked for each position."),
+    cl::location(llvm::PotentialConstantIntValuesState::MaxPotentialValues),
+    cl::init(7));
+
+template <>
+unsigned llvm::PotentialConstantIntValuesState::MaxPotentialValues = 0;
+
 STATISTIC(NumAAs, "Number of abstract attributes created");
 
 // Some helper macros to deal with statistics tracking.
@@ -120,6 +130,7 @@ PIPE_OPERATOR(AAMemoryLocation)
 PIPE_OPERATOR(AAValueConstantRange)
 PIPE_OPERATOR(AAPrivatizablePtr)
 PIPE_OPERATOR(AAUndefinedBehavior)
+PIPE_OPERATOR(AAPotentialValues)
 
 #undef PIPE_OPERATOR
 } // namespace llvm
@@ -7075,6 +7086,155 @@ struct AAValueConstantRangeCallSiteArgument : AAValueConstantRangeFloating {
     STATS_DECLTRACK_CSARG_ATTR(value_range)
   }
 };
+
+/// ------------------ Potential Values Attribute -------------------------
+
+struct AAPotentialValuesImpl : AAPotentialValues {
+  using StateType = PotentialConstantIntValuesState;
+
+  AAPotentialValuesImpl(const IRPosition &IRP, Attributor &A)
+      : AAPotentialValues(IRP, A) {}
+
+  /// See AbstractAttribute::getAsStr().
+  const std::string getAsStr() const override {
+    std::string Str;
+    llvm::raw_string_ostream OS(Str);
+    OS << getState();
+    return OS.str();
+  }
+
+  /// See AbstractAttribute::updateImpl(...).
+  ChangeStatus updateImpl(Attributor &A) override {
+    return indicatePessimisticFixpoint();
+  }
+};
+
+struct AAPotentialValuesArgument final
+    : AAArgumentFromCallSiteArguments<AAPotentialValues, AAPotentialValuesImpl,
+                                      PotentialConstantIntValuesState> {
+  using Base =
+      AAArgumentFromCallSiteArguments<AAPotentialValues, AAPotentialValuesImpl,
+                                      PotentialConstantIntValuesState>;
+  AAPotentialValuesArgument(const IRPosition &IRP, Attributor &A)
+      : Base(IRP, A) {}
+
+  /// See AbstractAttribute::initialize(..).
+  void initialize(Attributor &A) override {
+    if (!getAnchorScope() || getAnchorScope()->isDeclaration()) {
+      indicatePessimisticFixpoint();
+    } else {
+      Base::initialize(A);
+    }
+  }
+
+  /// See AbstractAttribute::trackStatistics()
+  void trackStatistics() const override {
+    STATS_DECLTRACK_ARG_ATTR(potential_values)
+  }
+};
+
+struct AAPotentialValuesReturned
+    : AAReturnedFromReturnedValues<AAPotentialValues, AAPotentialValuesImpl> {
+  using Base =
+      AAReturnedFromReturnedValues<AAPotentialValues, AAPotentialValuesImpl>;
+  AAPotentialValuesReturned(const IRPosition &IRP, Attributor &A)
+      : Base(IRP, A) {}
+
+  /// See AbstractAttribute::trackStatistics()
+  void trackStatistics() const override {
+    STATS_DECLTRACK_FNRET_ATTR(potential_values)
+  }
+};
+
+struct AAPotentialValuesFloating : AAPotentialValuesImpl {
+  AAPotentialValuesFloating(const IRPosition &IRP, Attributor &A)
+      : AAPotentialValuesImpl(IRP, A) {}
+
+  /// See AbstractAttribute::initialize(..).
+  void initialize(Attributor &A) override {
+    Value &V = getAssociatedValue();
+
+    if (auto *C = dyn_cast<ConstantInt>(&V)) {
+      unionAssumed(C->getValue());
+      indicateOptimisticFixpoint();
+      return;
+    }
+
+    if (isa<UndefValue>(&V)) {
+      // Collapse the undef state to 0.
+      unionAssumed(
+          APInt(/* numBits */ getAssociatedType()->getIntegerBitWidth(),
+                /* val */ 0));
+      indicateOptimisticFixpoint();
+      return;
+    }
+
+    if (isa<BinaryOperator>(&V) || isa<ICmpInst>(&V) || isa<CastInst>(&V))
+      return;
+
+    if (isa<SelectInst>(V) || isa<PHINode>(V))
+      return;
+
+    indicatePessimisticFixpoint();
+
+    LLVM_DEBUG(dbgs() << "[AAPotentialValues] We give up: "
+                      << getAssociatedValue() << "\n");
+  }
+
+  /// See AbstractAttribute::trackStatistics()
+  void trackStatistics() const override {
+    STATS_DECLTRACK_FLOATING_ATTR(potential_values)
+  }
+};
+
+struct AAPotentialValuesFunction : AAPotentialValuesImpl {
+  AAPotentialValuesFunction(const IRPosition &IRP, Attributor &A)
+      : AAPotentialValuesImpl(IRP, A) {}
+
+  /// See AbstractAttribute::initialize(...).
+  ChangeStatus updateImpl(Attributor &A) override {
+    llvm_unreachable("AAPotentialValues(Function|CallSite)::updateImpl will "
+                     "not be called");
+  }
+
+  /// See AbstractAttribute::trackStatistics()
+  void trackStatistics() const override {
+    STATS_DECLTRACK_FN_ATTR(potential_values)
+  }
+};
+
+struct AAPotentialValuesCallSite : AAPotentialValuesFunction {
+  AAPotentialValuesCallSite(const IRPosition &IRP, Attributor &A)
+      : AAPotentialValuesFunction(IRP, A) {}
+
+  /// See AbstractAttribute::trackStatistics()
+  void trackStatistics() const override {
+    STATS_DECLTRACK_CS_ATTR(potential_values)
+  }
+};
+
+struct AAPotentialValuesCallSiteReturned
+    : AACallSiteReturnedFromReturned<AAPotentialValues, AAPotentialValuesImpl> {
+  AAPotentialValuesCallSiteReturned(const IRPosition &IRP, Attributor &A)
+      : AACallSiteReturnedFromReturned<AAPotentialValues,
+                                       AAPotentialValuesImpl>(IRP, A) {}
+
+  /// See AbstractAttribute::trackStatistics()
+  void trackStatistics() const override {
+    STATS_DECLTRACK_CSRET_ATTR(potential_values)
+  }
+};
+
+struct AAPotentialValuesCallSiteArgument : AAPotentialValuesFloating {
+  AAPotentialValuesCallSiteArgument(const IRPosition &IRP, Attributor &A)
+      : AAPotentialValuesFloating(IRP, A) {}
+
+  /// See AbstractAttribute::trackStatistics()
+  void trackStatistics() const override {
+    STATS_DECLTRACK_CSARG_ATTR(potential_values)
+  }
+};
+
 } // namespace
 
 const char AAReturnedValues::ID = 0;
@@ -7098,6 +7258,7 @@ const char AAPrivatizablePtr::ID = 0;
 const char AAMemoryBehavior::ID = 0;
 const char AAMemoryLocation::ID = 0;
 const char AAValueConstantRange::ID = 0;
+const char AAPotentialValues::ID = 0;
 
 // Macro magic to create the static generator function for attributes that
 // follow the naming scheme.
@@ -7207,6 +7368,7 @@ CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION(AADereferenceable)
 CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAAlign)
 CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION(AANoCapture)
 CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAValueConstantRange)
+CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAPotentialValues)
 
 CREATE_ALL_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAValueSimplify)
 CREATE_ALL_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAIsDead)

test/Transforms/Attributor/potential.ll

@@ -0,0 +1,394 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --function-signature --scrub-attributes
+; RUN: opt -attributor -attributor-manifest-internal  -attributor-max-iterations-verify -attributor-annotate-decl-cs -attributor-max-iterations=9 -S < %s | FileCheck %s --check-prefixes=CHECK,NOT_CGSCC_NPM,NOT_CGSCC_OPM,NOT_TUNIT_NPM,IS__TUNIT____,IS________OPM,IS__TUNIT_OPM
+; RUN: opt -aa-pipeline=basic-aa -passes=attributor -attributor-manifest-internal  -attributor-max-iterations-verify -attributor-annotate-decl-cs -attributor-max-iterations=7 -S < %s | FileCheck %s --check-prefixes=CHECK,NOT_CGSCC_OPM,NOT_CGSCC_NPM,NOT_TUNIT_OPM,IS__TUNIT____,IS________NPM,IS__TUNIT_NPM
+; RUN: opt -attributor-cgscc -attributor-manifest-internal  -attributor-annotate-decl-cs -S < %s | FileCheck %s --check-prefixes=CHECK,NOT_TUNIT_NPM,NOT_TUNIT_OPM,NOT_CGSCC_NPM,IS__CGSCC____,IS________OPM,IS__CGSCC_OPM
+; RUN: opt -aa-pipeline=basic-aa -passes=attributor-cgscc -attributor-manifest-internal  -attributor-annotate-decl-cs -S < %s | FileCheck %s --check-prefixes=CHECK,NOT_TUNIT_NPM,NOT_TUNIT_OPM,NOT_CGSCC_OPM,IS__CGSCC____,IS________NPM,IS__CGSCC_NPM
+;
+; Test for multiple potential values
+;
+; potential-test 1
+; bool iszero(int c) { return c == 0; }
+; bool potential_test1(bool c) { return iszero(c ? 1 : -1); }
+
+define internal i1 @iszero1(i32 %c) {
+; CHECK-LABEL: define {{[^@]+}}@iszero1
+; CHECK-SAME: (i32 [[C:%.*]])
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[C]], 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = icmp eq i32 %c, 0
+  ret i1 %cmp
+}
+
+define i1 @potential_test1(i1 %c) {
+; CHECK-LABEL: define {{[^@]+}}@potential_test1
+; CHECK-SAME: (i1 [[C:%.*]])
+; CHECK-NEXT:    [[ARG:%.*]] = select i1 [[C]], i32 -1, i32 1
+; CHECK-NEXT:    [[RET:%.*]] = call i1 @iszero1(i32 [[ARG]])
+; CHECK-NEXT:    ret i1 [[RET]]
+;
+  %arg = select i1 %c, i32 -1, i32 1
+  %ret = call i1 @iszero1(i32 %arg)
+  ret i1 %ret
+}
+
+
+; potential-test 2
+;
+; potential values of argument of iszero are {1,-1}
+; potential value of returned value of iszero is 0
+;
+; int call_with_two_values(int x) { return iszero(x) + iszero(-x); }
+; int potential_test2(int x) { return call_with_two_values(1) + call_with_two_values(-1); }
+
+define internal i32 @iszero2(i32 %c) {
+; CHECK-LABEL: define {{[^@]+}}@iszero2
+; CHECK-SAME: (i32 [[C:%.*]])
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[C]], 0
+; CHECK-NEXT:    [[RET:%.*]] = zext i1 [[CMP]] to i32
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp eq i32 %c, 0
+  %ret = zext i1 %cmp to i32
+  ret i32 %ret
+}
+
+define internal i32 @call_with_two_values(i32 %c) {
+; IS__TUNIT____-LABEL: define {{[^@]+}}@call_with_two_values
+; IS__TUNIT____-SAME: (i32 [[C:%.*]])
+; IS__TUNIT____-NEXT:    [[CSRET1:%.*]] = call i32 @iszero2(i32 [[C]]) #0, !range !0
+; IS__TUNIT____-NEXT:    [[MINUSC:%.*]] = sub i32 0, [[C]]
+; IS__TUNIT____-NEXT:    [[CSRET2:%.*]] = call i32 @iszero2(i32 [[MINUSC]]) #0, !range !0
+; IS__TUNIT____-NEXT:    [[RET:%.*]] = add i32 [[CSRET1]], [[CSRET2]]
+; IS__TUNIT____-NEXT:    ret i32 [[RET]]
+;
+; IS__CGSCC____-LABEL: define {{[^@]+}}@call_with_two_values
+; IS__CGSCC____-SAME: (i32 [[C:%.*]])
+; IS__CGSCC____-NEXT:    [[CSRET1:%.*]] = call i32 @iszero2(i32 [[C]])
+; IS__CGSCC____-NEXT:    [[MINUSC:%.*]] = sub i32 0, [[C]]
+; IS__CGSCC____-NEXT:    [[CSRET2:%.*]] = call i32 @iszero2(i32 [[MINUSC]])
+; IS__CGSCC____-NEXT:    [[RET:%.*]] = add i32 [[CSRET1]], [[CSRET2]]
+; IS__CGSCC____-NEXT:    ret i32 [[RET]]
+;
+  %csret1 = call i32 @iszero2(i32 %c)
+  %minusc = sub i32 0, %c
+  %csret2 = call i32 @iszero2(i32 %minusc)
+  %ret = add i32 %csret1, %csret2
+  ret i32 %ret
+}
+
+define i32 @potential_test2(i1 %c) {
+; IS__TUNIT____-LABEL: define {{[^@]+}}@potential_test2
+; IS__TUNIT____-SAME: (i1 [[C:%.*]])
+; IS__TUNIT____-NEXT:    [[CSRET1:%.*]] = call i32 @call_with_two_values(i32 1) #0, !range !1
+; IS__TUNIT____-NEXT:    [[CSRET2:%.*]] = call i32 @call_with_two_values(i32 -1) #1, !range !1
+; IS__TUNIT____-NEXT:    [[RET:%.*]] = add i32 [[CSRET1]], [[CSRET2]]
+; IS__TUNIT____-NEXT:    ret i32 [[RET]]
+;
+; IS__CGSCC____-LABEL: define {{[^@]+}}@potential_test2
+; IS__CGSCC____-SAME: (i1 [[C:%.*]])
+; IS__CGSCC____-NEXT:    [[CSRET1:%.*]] = call i32 @call_with_two_values(i32 1)
+; IS__CGSCC____-NEXT:    [[CSRET2:%.*]] = call i32 @call_with_two_values(i32 -1)
+; IS__CGSCC____-NEXT:    [[RET:%.*]] = add i32 [[CSRET1]], [[CSRET2]]
+; IS__CGSCC____-NEXT:    ret i32 [[RET]]
+;
+  %csret1 = call i32 @call_with_two_values(i32 1)
+  %csret2 = call i32 @call_with_two_values(i32 -1)
+  %ret = add i32 %csret1, %csret2
+  ret i32 %ret
+}
+
+
+; potential-test 3
+;
+; potential values of returned value of f are {0,1}
+; potential values of argument of g are {0,1}
+; potential value of returned value of g is 1
+; then returned value of g can be simplified
+;
+; int zero_or_one(int c) { return c < 2; }
+; int potential_test3() { return zero_or_one(iszero(0))+zero_or_one(iszero(1)); }
+
+define internal i32 @iszero3(i32 %c) {
+; CHECK-LABEL: define {{[^@]+}}@iszero3
+; CHECK-SAME: (i32 [[C:%.*]])
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[C]], 0
+; CHECK-NEXT:    [[RET:%.*]] = zext i1 [[CMP]] to i32
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp eq i32 %c, 0
+  %ret = zext i1 %cmp to i32
+  ret i32 %ret
+}
+
+define internal i32 @less_than_two(i32 %c) {
+; CHECK-LABEL: define {{[^@]+}}@less_than_two
+; CHECK-SAME: (i32 [[C:%.*]])
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[C]], 2
+; CHECK-NEXT:    [[RET:%.*]] = zext i1 [[CMP]] to i32
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp slt i32 %c, 2
+  %ret = zext i1 %cmp to i32
+  ret i32 %ret
+}
+
+define i32 @potential_test3() {
+; NOT_TUNIT_NPM-LABEL: define {{[^@]+}}@potential_test3()
+; NOT_TUNIT_NPM-NEXT:    [[CMP1:%.*]] = call i32 @iszero3(i32 0)
+; NOT_TUNIT_NPM-NEXT:    [[TRUE1:%.*]] = call i32 @less_than_two(i32 [[CMP1]])
+; NOT_TUNIT_NPM-NEXT:    [[CMP2:%.*]] = call i32 @iszero3(i32 1)
+; NOT_TUNIT_NPM-NEXT:    [[TRUE2:%.*]] = call i32 @less_than_two(i32 [[CMP2]])
+; NOT_TUNIT_NPM-NEXT:    [[RET:%.*]] = add i32 [[TRUE1]], [[TRUE2]]
+; NOT_TUNIT_NPM-NEXT:    ret i32 [[RET]]
+;
+; IS__TUNIT_NPM-LABEL: define {{[^@]+}}@potential_test3()
+; IS__TUNIT_NPM-NEXT:    [[CMP1:%.*]] = call i32 @iszero3(i32 0) #0, !range !0
+; IS__TUNIT_NPM-NEXT:    [[TRUE1:%.*]] = call i32 @less_than_two(i32 [[CMP1]]) #0, !range !0
+; IS__TUNIT_NPM-NEXT:    [[CMP2:%.*]] = call i32 @iszero3(i32 1) #0, !range !0
+; IS__TUNIT_NPM-NEXT:    [[TRUE2:%.*]] = call i32 @less_than_two(i32 [[CMP2]]) #0, !range !0
+; IS__TUNIT_NPM-NEXT:    [[RET:%.*]] = add i32 [[TRUE1]], [[TRUE2]]
+; IS__TUNIT_NPM-NEXT:    ret i32 [[RET]]
+;
+  %cmp1 = call i32 @iszero3(i32 0)
+  %true1 = call i32 @less_than_two(i32 %cmp1)
+  %cmp2 = call i32 @iszero3(i32 1)
+  %true2 = call i32 @less_than_two(i32 %cmp2)
+  %ret = add i32 %true1, %true2
+  ret i32 %ret
+}
+
+
+; potential-test 4,5
+;
+; simplified
+; int potential_test4(int c) { return return1or3(c) == 2; }
+; int potential_test5(int c) { return return1or3(c) == return2or4(c); }
+;
+; not simplified
+; int potential_test6(int c) { return return1or3(c) == 3; }
+; int potential_test7(int c) { return return1or3(c) == return3or4(c); }
+
+define i32 @potential_test4(i32 %c) {
+; IS__TUNIT____-LABEL: define {{[^@]+}}@potential_test4
+; IS__TUNIT____-SAME: (i32 [[C:%.*]])
+; IS__TUNIT____-NEXT:    [[CSRET:%.*]] = call i32 @return1or3(i32 [[C]]) #0, !range !2
+; IS__TUNIT____-NEXT:    [[FALSE:%.*]] = icmp eq i32 [[CSRET]], 2
+; IS__TUNIT____-NEXT:    [[RET:%.*]] = zext i1 [[FALSE]] to i32
+; IS__TUNIT____-NEXT:    ret i32 [[RET]]
+;
+; IS__CGSCC____-LABEL: define {{[^@]+}}@potential_test4
+; IS__CGSCC____-SAME: (i32 [[C:%.*]])
+; IS__CGSCC____-NEXT:    [[CSRET:%.*]] = call i32 @return1or3(i32 [[C]])
+; IS__CGSCC____-NEXT:    [[FALSE:%.*]] = icmp eq i32 [[CSRET]], 2
+; IS__CGSCC____-NEXT:    [[RET:%.*]] = zext i1 [[FALSE]] to i32
+; IS__CGSCC____-NEXT:    ret i32 [[RET]]
+;
+  %csret = call i32 @return1or3(i32 %c)
+  %false = icmp eq i32 %csret, 2
+  %ret = zext i1 %false to i32
+  ret i32 %ret
+}
+
+define i32 @potential_test5(i32 %c) {
+; IS__TUNIT____-LABEL: define {{[^@]+}}@potential_test5
+; IS__TUNIT____-SAME: (i32 [[C:%.*]])
+; IS__TUNIT____-NEXT:    [[CSRET1:%.*]] = call i32 @return1or3(i32 [[C]]) #0, !range !2
+; IS__TUNIT____-NEXT:    [[CSRET2:%.*]] = call i32 @return2or4(i32 [[C]]) #0, !range !3
+; IS__TUNIT____-NEXT:    [[FALSE:%.*]] = icmp eq i32 [[CSRET1]], [[CSRET2]]
+; IS__TUNIT____-NEXT:    [[RET:%.*]] = zext i1 [[FALSE]] to i32
+; IS__TUNIT____-NEXT:    ret i32 [[RET]]
+;
+; IS__CGSCC____-LABEL: define {{[^@]+}}@potential_test5
+; IS__CGSCC____-SAME: (i32 [[C:%.*]])
+; IS__CGSCC____-NEXT:    [[CSRET1:%.*]] = call i32 @return1or3(i32 [[C]])
+; IS__CGSCC____-NEXT:    [[CSRET2:%.*]] = call i32 @return2or4(i32 [[C]])
+; IS__CGSCC____-NEXT:    [[FALSE:%.*]] = icmp eq i32 [[CSRET1]], [[CSRET2]]
+; IS__CGSCC____-NEXT:    [[RET:%.*]] = zext i1 [[FALSE]] to i32
+; IS__CGSCC____-NEXT:    ret i32 [[RET]]
+;
+  %csret1 = call i32 @return1or3(i32 %c)
+  %csret2 = call i32 @return2or4(i32 %c)
+  %false = icmp eq i32 %csret1, %csret2
+  %ret = zext i1 %false to i32
+  ret i32 %ret
+}
+
+define i1 @potential_test6(i32 %c) {
+; IS__TUNIT____-LABEL: define {{[^@]+}}@potential_test6
+; IS__TUNIT____-SAME: (i32 [[C:%.*]])
+; IS__TUNIT____-NEXT:    [[CSRET1:%.*]] = call i32 @return1or3(i32 [[C]]) #0, !range !2
+; IS__TUNIT____-NEXT:    [[RET:%.*]] = icmp eq i32 [[CSRET1]], 3
+; IS__TUNIT____-NEXT:    ret i1 [[RET]]
+;
+; IS__CGSCC____-LABEL: define {{[^@]+}}@potential_test6
+; IS__CGSCC____-SAME: (i32 [[C:%.*]])
+; IS__CGSCC____-NEXT:    [[CSRET1:%.*]] = call i32 @return1or3(i32 [[C]])
+; IS__CGSCC____-NEXT:    [[RET:%.*]] = icmp eq i32 [[CSRET1]], 3
+; IS__CGSCC____-NEXT:    ret i1 [[RET]]
+;
+  %csret1 = call i32 @return1or3(i32 %c)
+  %ret = icmp eq i32 %csret1, 3
+  ret i1 %ret
+}
+
+define i1 @potential_test7(i32 %c) {
+; IS__TUNIT____-LABEL: define {{[^@]+}}@potential_test7
+; IS__TUNIT____-SAME: (i32 [[C:%.*]])
+; IS__TUNIT____-NEXT:    [[CSRET1:%.*]] = call i32 @return1or3(i32 [[C]]) #0, !range !2
+; IS__TUNIT____-NEXT:    [[CSRET2:%.*]] = call i32 @return3or4(i32 [[C]]) #0, !range !4
+; IS__TUNIT____-NEXT:    [[RET:%.*]] = icmp eq i32 [[CSRET1]], [[CSRET2]]
+; IS__TUNIT____-NEXT:    ret i1 [[RET]]
+;
+; IS__CGSCC____-LABEL: define {{[^@]+}}@potential_test7
+; IS__CGSCC____-SAME: (i32 [[C:%.*]])
+; IS__CGSCC____-NEXT:    [[CSRET1:%.*]] = call i32 @return1or3(i32 [[C]])
+; IS__CGSCC____-NEXT:    [[CSRET2:%.*]] = call i32 @return3or4(i32 [[C]])
+; IS__CGSCC____-NEXT:    [[RET:%.*]] = icmp eq i32 [[CSRET1]], [[CSRET2]]
+; IS__CGSCC____-NEXT:    ret i1 [[RET]]
+;
+  %csret1 = call i32 @return1or3(i32 %c)
+  %csret2 = call i32 @return3or4(i32 %c)
+  %ret = icmp eq i32 %csret1, %csret2
+  ret i1 %ret
+}
+
+define internal i32 @return1or3(i32 %c) {
+; CHECK-LABEL: define {{[^@]+}}@return1or3
+; CHECK-SAME: (i32 [[C:%.*]])
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[C]], 0
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 1, i32 3
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp eq i32 %c, 0
+  %ret = select i1 %cmp, i32 1, i32 3
+  ret i32 %ret
+}
+
+define internal i32 @return2or4(i32 %c) {
+; CHECK-LABEL: define {{[^@]+}}@return2or4
+; CHECK-SAME: (i32 [[C:%.*]])
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[C]], 0
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 2, i32 4
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp eq i32 %c, 0
+  %ret = select i1 %cmp, i32 2, i32 4
+  ret i32 %ret
+}
+
+define internal i32 @return3or4(i32 %c) {
+; CHECK-LABEL: define {{[^@]+}}@return3or4
+; CHECK-SAME: (i32 [[C:%.*]])
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[C]], 0
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 3, i32 4
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp eq i32 %c, 0
+  %ret = select i1 %cmp, i32 3, i32 4
+  ret i32 %ret
+}
+
+; potential-test 8
+;
+; propagate argument to callsite argument
+
+define internal i1 @cmp_with_four(i32 %c) {
+; CHECK-LABEL: define {{[^@]+}}@cmp_with_four
+; CHECK-SAME: (i32 [[C:%.*]])
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[C]], 4
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = icmp eq i32 %c, 4
+  ret i1 %cmp
+}
+
+define internal i1 @wrapper(i32 %c) {
+; CHECK-LABEL: define {{[^@]+}}@wrapper
+; CHECK-SAME: (i32 [[C:%.*]])
+; CHECK-NEXT:    [[RET:%.*]] = call i1 @cmp_with_four(i32 [[C]])
+; CHECK-NEXT:    ret i1 [[RET]]
+;
+  %ret = call i1 @cmp_with_four(i32 %c)
+  ret i1 %ret
+}
+
+define i1 @potential_test8() {
+; CHECK-LABEL: define {{[^@]+}}@potential_test8()
+; CHECK-NEXT:    [[RES1:%.*]] = call i1 @wrapper(i32 1)
+; CHECK-NEXT:    [[RES3:%.*]] = call i1 @wrapper(i32 3)
+; CHECK-NEXT:    [[RES5:%.*]] = call i1 @wrapper(i32 5)
+; CHECK-NEXT:    [[RES13:%.*]] = or i1 [[RES1]], [[RES3]]
+; CHECK-NEXT:    [[RES135:%.*]] = or i1 [[RES13]], [[RES5]]
+; CHECK-NEXT:    ret i1 [[RES135]]
+;
+  %res1 = call i1 @wrapper(i32 1)
+  %res3 = call i1 @wrapper(i32 3)
+  %res5 = call i1 @wrapper(i32 5)
+  %res13 = or i1 %res1, %res3
+  %res135 =  or i1 %res13, %res5
+  ret i1 %res135
+}
+
+define i1 @potential_test9() {
+; IS________OPM-LABEL: define {{[^@]+}}@potential_test9()
+; IS________OPM-NEXT:  entry:
+; IS________OPM-NEXT:    br label [[COND:%.*]]
+; IS________OPM:       cond:
+; IS________OPM-NEXT:    [[I_0:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_1:%.*]], [[INC:%.*]] ]
+; IS________OPM-NEXT:    [[C_0:%.*]] = phi i32 [ 1, [[ENTRY]] ], [ [[C_1:%.*]], [[INC]] ]
+; IS________OPM-NEXT:    [[CMP:%.*]] = icmp slt i32 [[I_0]], 10
+; IS________OPM-NEXT:    br i1 [[CMP]], label [[BODY:%.*]], label [[END:%.*]]
+; IS________OPM:       body:
+; IS________OPM-NEXT:    [[C_1]] = mul i32 [[C_0]], -1
+; IS________OPM-NEXT:    br label [[INC]]
+; IS________OPM:       inc:
+; IS________OPM-NEXT:    [[I_1]] = add i32 [[I_0]], 1
+; IS________OPM-NEXT:    br label [[COND]]
+; IS________OPM:       end:
+; IS________OPM-NEXT:    [[RET:%.*]] = icmp eq i32 [[C_0]], 0
+; IS________OPM-NEXT:    ret i1 [[RET]]
+;
+; IS________NPM-LABEL: define {{[^@]+}}@potential_test9()
+; IS________NPM-NEXT:  entry:
+; IS________NPM-NEXT:    br label [[COND:%.*]]
+; IS________NPM:       cond:
+; IS________NPM-NEXT:    [[I_0:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_1:%.*]], [[INC:%.*]] ]
+; IS________NPM-NEXT:    [[C_0:%.*]] = phi i32 [ 1, [[ENTRY]] ], [ [[C_1:%.*]], [[INC]] ]
+; IS________NPM-NEXT:    [[CMP:%.*]] = icmp slt i32 [[I_0]], 10
+; IS________NPM-NEXT:    br i1 [[CMP]], label [[BODY:%.*]], label [[END:%.*]]
+; IS________NPM:       body:
+; IS________NPM-NEXT:    [[C_1]] = mul i32 [[C_0]], -1
+; IS________NPM-NEXT:    br label [[INC]]
+; IS________NPM:       inc:
+; IS________NPM-NEXT:    [[I_1]] = add i32 [[I_0]], 1
+; IS________NPM-NEXT:    br label [[COND]]
+; IS________NPM:       end:
+; IS________NPM-NEXT:    ret i1 false
+;
+entry:
+  br label %cond
+cond:
+  %i.0 = phi i32 [0, %entry], [%i.1, %inc]
+  %c.0 = phi i32 [1, %entry], [%c.1, %inc]
+  %cmp = icmp slt i32 %i.0, 10
+  br i1 %cmp, label %body, label %end
+body:
+  %c.1 = mul i32 %c.0, -1
+  br label %inc
+inc:
+  %i.1 = add i32 %i.0, 1
+  br label %cond
+end:
+  %ret = icmp eq i32 %c.0, 0
+  ret i1 %ret
+}
+
+; IS__TUNIT____: !0 = !{i32 0, i32 2}
+; IS__TUNIT____: !1 = !{i32 0, i32 3}
+; IS__TUNIT____: !2 = !{i32 1, i32 4}
+; IS__TUNIT____: !3 = !{i32 2, i32 5}
+; IS__TUNIT____: !4 = !{i32 3, i32 5}
+; IS__TUNIT____-NOT: !5
+
+; NOT_TUNIT____-NOT: !0