Refactor: Use interval analysis for symbolic values for inferCondtion (#3488)

Makefile

@@ -194,6 +194,7 @@ LIBOBJ =      $(libcppdir)/analyzerinfo.o \
               $(libcppdir)/exprengine.o \
               $(libcppdir)/forwardanalyzer.o \
               $(libcppdir)/importproject.o \
+              $(libcppdir)/infer.o \
               $(libcppdir)/library.o \
               $(libcppdir)/mathlib.o \
               $(libcppdir)/path.o \
@@ -521,6 +522,9 @@ $(libcppdir)/forwardanalyzer.o: lib/forwardanalyzer.cpp lib/analyzer.h lib/astut
 $(libcppdir)/importproject.o: lib/importproject.cpp externals/picojson/picojson.h externals/tinyxml2/tinyxml2.h lib/astutils.h lib/config.h lib/errortypes.h lib/importproject.h lib/library.h lib/mathlib.h lib/path.h lib/platform.h lib/settings.h lib/standards.h lib/suppressions.h lib/templatesimplifier.h lib/timer.h lib/token.h lib/tokenize.h lib/tokenlist.h lib/utils.h lib/valueflow.h
 	$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CPPFILESDIR) $(CXXFLAGS) $(UNDEF_STRICT_ANSI) -c -o $(libcppdir)/importproject.o $(libcppdir)/importproject.cpp
 
+$(libcppdir)/infer.o: lib/infer.cpp lib/astutils.h lib/calculate.h lib/config.h lib/errortypes.h lib/infer.h lib/mathlib.h lib/utils.h lib/valueflow.h lib/valueptr.h
+	$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CPPFILESDIR) $(CXXFLAGS) $(UNDEF_STRICT_ANSI) -c -o $(libcppdir)/infer.o $(libcppdir)/infer.cpp
+
 $(libcppdir)/library.o: lib/library.cpp externals/tinyxml2/tinyxml2.h lib/astutils.h lib/config.h lib/errortypes.h lib/library.h lib/mathlib.h lib/path.h lib/standards.h lib/symboldatabase.h lib/templatesimplifier.h lib/token.h lib/tokenlist.h lib/utils.h lib/valueflow.h
 	$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CPPFILESDIR) $(CXXFLAGS) $(UNDEF_STRICT_ANSI) -c -o $(libcppdir)/library.o $(libcppdir)/library.cpp
 
@@ -578,7 +582,7 @@ $(libcppdir)/tokenlist.o: lib/tokenlist.cpp externals/simplecpp/simplecpp.h lib/
 $(libcppdir)/utils.o: lib/utils.cpp lib/config.h lib/utils.h
 	$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CPPFILESDIR) $(CXXFLAGS) $(UNDEF_STRICT_ANSI) -c -o $(libcppdir)/utils.o $(libcppdir)/utils.cpp
 
-$(libcppdir)/valueflow.o: lib/valueflow.cpp lib/analyzer.h lib/astutils.h lib/calculate.h lib/check.h lib/checkuninitvar.h lib/color.h lib/config.h lib/ctu.h lib/errorlogger.h lib/errortypes.h lib/forwardanalyzer.h lib/importproject.h lib/library.h lib/mathlib.h lib/path.h lib/platform.h lib/programmemory.h lib/reverseanalyzer.h lib/settings.h lib/standards.h lib/suppressions.h lib/symboldatabase.h lib/templatesimplifier.h lib/timer.h lib/token.h lib/tokenlist.h lib/utils.h lib/valueflow.h lib/valueptr.h
+$(libcppdir)/valueflow.o: lib/valueflow.cpp lib/analyzer.h lib/astutils.h lib/calculate.h lib/check.h lib/checkuninitvar.h lib/color.h lib/config.h lib/ctu.h lib/errorlogger.h lib/errortypes.h lib/forwardanalyzer.h lib/importproject.h lib/infer.h lib/library.h lib/mathlib.h lib/path.h lib/platform.h lib/programmemory.h lib/reverseanalyzer.h lib/settings.h lib/standards.h lib/suppressions.h lib/symboldatabase.h lib/templatesimplifier.h lib/timer.h lib/token.h lib/tokenlist.h lib/utils.h lib/valueflow.h lib/valueptr.h
 	$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CPPFILESDIR) $(CXXFLAGS) $(UNDEF_STRICT_ANSI) -c -o $(libcppdir)/valueflow.o $(libcppdir)/valueflow.cpp
 
 cli/cmdlineparser.o: cli/cmdlineparser.cpp cli/cmdlineparser.h cli/cppcheckexecutor.h cli/filelister.h cli/threadexecutor.h externals/tinyxml2/tinyxml2.h lib/check.h lib/color.h lib/config.h lib/errorlogger.h lib/errortypes.h lib/importproject.h lib/library.h lib/mathlib.h lib/path.h lib/platform.h lib/settings.h lib/standards.h lib/suppressions.h lib/timer.h lib/utils.h

lib/infer.cpp

@@ -0,0 +1,362 @@
+#include "infer.h"
+#include "calculate.h"
+#include "valueptr.h"
+#include <iterator>
+#include <unordered_set>
+
+template<class Predicate, class Compare>
+static const ValueFlow::Value* getCompareValue(const std::list<ValueFlow::Value>& values, Predicate pred, Compare compare)
+{
+    const ValueFlow::Value* result = nullptr;
+    for (const ValueFlow::Value& value : values) {
+        if (!pred(value))
+            continue;
+        if (result)
+            result = &std::min(value, *result, [compare](const ValueFlow::Value& x, const ValueFlow::Value& y) {
+                return compare(x.intvalue, y.intvalue);
+            });
+        else
+            result = &value;
+    }
+    return result;
+}
+
+struct Interval {
+    std::vector<MathLib::bigint> minvalue = {};
+    std::vector<MathLib::bigint> maxvalue = {};
+    std::vector<const ValueFlow::Value*> minRef = {};
+    std::vector<const ValueFlow::Value*> maxRef = {};
+
+    std::string str() const
+    {
+        std::string result = "[";
+        if (minvalue.size() == 1)
+            result += std::to_string(minvalue.front());
+        else
+            result += "*";
+        result += ",";
+        if (maxvalue.size() == 1)
+            result += std::to_string(maxvalue.front());
+        else
+            result += "*";
+        result += "]";
+        return result;
+    }
+
+    void setMinValue(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
+    {
+        minvalue = {x};
+        if (ref)
+            minRef = {ref};
+    }
+
+    void setMaxValue(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
+    {
+        maxvalue = {x};
+        if (ref)
+            maxRef = {ref};
+    }
+
+    bool isLessThan(MathLib::bigint x, std::vector<const ValueFlow::Value*>* ref = nullptr) const
+    {
+        if (!this->maxvalue.empty() && this->maxvalue.front() < x) {
+            if (ref)
+                *ref = maxRef;
+            return true;
+        }
+        return false;
+    }
+
+    bool isGreaterThan(MathLib::bigint x, std::vector<const ValueFlow::Value*>* ref = nullptr) const
+    {
+        if (!this->minvalue.empty() && this->minvalue.front() > x) {
+            if (ref)
+                *ref = minRef;
+            return true;
+        }
+        return false;
+    }
+
+    bool isScalar() const {
+        return minvalue.size() == 1 && minvalue == maxvalue;
+    }
+
+    bool empty() const {
+        return minvalue.empty() && maxvalue.empty();
+    }
+
+    bool isScalarOrEmpty() const {
+        return empty() || isScalar();
+    }
+
+    MathLib::bigint getScalar() const
+    {
+        assert(isScalar());
+        return minvalue.front();
+    }
+
+    std::vector<const ValueFlow::Value*> getScalarRef() const
+    {
+        assert(isScalar());
+        if (minRef != maxRef)
+            return merge(minRef, maxRef);
+        return minRef;
+    }
+
+    static Interval fromInt(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
+    {
+        Interval result;
+        result.setMinValue(x, ref);
+        result.setMaxValue(x, ref);
+        return result;
+    }
+
+    template<class Predicate>
+    static Interval fromValues(const std::list<ValueFlow::Value>& values, Predicate predicate)
+    {
+        Interval result;
+        const ValueFlow::Value* minValue = getCompareValue(values, predicate, std::less<MathLib::bigint>{});
+        if (minValue) {
+            if (minValue->isImpossible() && minValue->bound == ValueFlow::Value::Bound::Upper)
+                result.setMinValue(minValue->intvalue + 1, minValue);
+            if (minValue->isPossible() && minValue->bound == ValueFlow::Value::Bound::Lower)
+                result.setMinValue(minValue->intvalue, minValue);
+            if (minValue->isKnown())
+                return Interval::fromInt(minValue->intvalue, minValue);
+        }
+        const ValueFlow::Value* maxValue = getCompareValue(values, predicate, std::greater<MathLib::bigint>{});
+        if (maxValue) {
+            if (maxValue->isImpossible() && maxValue->bound == ValueFlow::Value::Bound::Lower)
+                result.setMaxValue(maxValue->intvalue - 1, maxValue);
+            if (maxValue->isPossible() && maxValue->bound == ValueFlow::Value::Bound::Upper)
+                result.setMaxValue(maxValue->intvalue, maxValue);
+            assert(!maxValue->isKnown());
+        }
+        return result;
+    }
+
+    static Interval fromValues(const std::list<ValueFlow::Value>& values)
+    {
+        return Interval::fromValues(values, [](const ValueFlow::Value&) {
+            return true;
+        });
+    }
+
+    template<class F>
+    static std::vector<MathLib::bigint> apply(const std::vector<MathLib::bigint>& x,
+                                              const std::vector<MathLib::bigint>& y,
+                                              F f)
+    {
+        if (x.empty())
+            return {};
+        if (y.empty())
+            return {};
+        return {f(x.front(), y.front())};
+    }
+
+    static std::vector<const ValueFlow::Value*> merge(std::vector<const ValueFlow::Value*> x,
+                                                      const std::vector<const ValueFlow::Value*>& y)
+    {
+        x.insert(x.end(), y.begin(), y.end());
+        return x;
+    }
+
+    friend Interval operator-(const Interval& lhs, const Interval& rhs)
+    {
+        Interval result;
+        result.minvalue = Interval::apply(lhs.minvalue, rhs.maxvalue, std::minus<MathLib::bigint>{});
+        result.maxvalue = Interval::apply(lhs.maxvalue, rhs.minvalue, std::minus<MathLib::bigint>{});
+        if (!result.minvalue.empty())
+            result.minRef = merge(lhs.minRef, rhs.maxRef);
+        if (!result.maxvalue.empty())
+            result.maxRef = merge(lhs.maxRef, rhs.minRef);
+        return result;
+    }
+
+    static std::vector<int> equal(const Interval& lhs,
+                                  const Interval& rhs,
+                                  std::vector<const ValueFlow::Value*>* ref = nullptr)
+    {
+        if (!lhs.isScalar())
+            return {};
+        if (!rhs.isScalar())
+            return {};
+        if (ref)
+            *ref = merge(lhs.getScalarRef(), rhs.getScalarRef());
+        return {lhs.minvalue == rhs.minvalue};
+    }
+
+    static std::vector<int> compare(const Interval& lhs,
+                                    const Interval& rhs,
+                                    std::vector<const ValueFlow::Value*>* ref = nullptr)
+    {
+        Interval diff = lhs - rhs;
+        if (diff.isGreaterThan(0, ref))
+            return {1};
+        if (diff.isLessThan(0, ref))
+            return {-1};
+        std::vector<int> eq = Interval::equal(lhs, rhs, ref);
+        if (!eq.empty()) {
+            if (eq.front() == 0)
+                return {1, -1};
+            else
+                return {0};
+        }
+        if (diff.isGreaterThan(-1, ref))
+            return {0, 1};
+        if (diff.isLessThan(1, ref))
+            return {0, -1};
+        return {};
+    }
+
+    static std::vector<bool> compare(const std::string& op,
+                                     const Interval& lhs,
+                                     const Interval& rhs,
+                                     std::vector<const ValueFlow::Value*>* ref = nullptr)
+    {
+        std::vector<int> r = compare(lhs, rhs, ref);
+        if (r.empty())
+            return {};
+        bool b = calculate(op, r.front(), 0);
+        if (std::all_of(r.begin() + 1, r.end(), [&](int i) {
+            return b == calculate(op, i, 0);
+        }))
+            return {b};
+        return {};
+    }
+};
+
+std::string toString(const Interval& i) {
+    return i.str();
+}
+
+static void addToErrorPath(ValueFlow::Value& value, const std::vector<const ValueFlow::Value*>& refs)
+{
+    std::unordered_set<const Token*> locations;
+    for (const ValueFlow::Value* ref : refs) {
+        if (ref->condition && !value.condition)
+            value.condition = ref->condition;
+        std::copy_if(ref->errorPath.begin(),
+                     ref->errorPath.end(),
+                     std::back_inserter(value.errorPath),
+                     [&](const ErrorPathItem& e) {
+            return locations.insert(e.first).second;
+        });
+    }
+}
+
+static void setValueKind(ValueFlow::Value& value, const std::vector<const ValueFlow::Value*>& refs)
+{
+    bool isPossible = false;
+    bool isInconclusive = false;
+    for (const ValueFlow::Value* ref : refs) {
+        if (ref->isPossible())
+            isPossible = true;
+        if (ref->isInconclusive())
+            isInconclusive = true;
+    }
+    if (isInconclusive)
+        value.setInconclusive();
+    else if (isPossible)
+        value.setPossible();
+    else
+        value.setKnown();
+}
+
+static bool inferNotEqual(const std::list<ValueFlow::Value>& values, MathLib::bigint x)
+{
+    return std::any_of(values.begin(), values.end(), [&](const ValueFlow::Value& value) {
+        return value.isImpossible() && value.intvalue == x;
+    });
+}
+
+std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
+                                    const std::string& op,
+                                    std::list<ValueFlow::Value> lhsValues,
+                                    std::list<ValueFlow::Value> rhsValues)
+{
+    std::vector<ValueFlow::Value> result;
+    auto notMatch = [&](const ValueFlow::Value& value) {
+        return !model->match(value);
+    };
+    lhsValues.remove_if(notMatch);
+    rhsValues.remove_if(notMatch);
+    if (lhsValues.empty() || rhsValues.empty())
+        return result;
+
+    Interval lhs = Interval::fromValues(lhsValues);
+    Interval rhs = Interval::fromValues(rhsValues);
+
+    if (op == "-") {
+        Interval diff = lhs - rhs;
+        if (diff.isScalar()) {
+            std::vector<const ValueFlow::Value*> refs = diff.getScalarRef();
+            ValueFlow::Value value(diff.getScalar());
+            addToErrorPath(value, refs);
+            setValueKind(value, refs);
+            result.push_back(value);
+        } else {
+            if (!diff.minvalue.empty()) {
+                ValueFlow::Value value(diff.minvalue.front() - 1);
+                value.setImpossible();
+                value.bound = ValueFlow::Value::Bound::Upper;
+                addToErrorPath(value, diff.minRef);
+                result.push_back(value);
+            }
+            if (!diff.maxvalue.empty()) {
+                ValueFlow::Value value(diff.maxvalue.front() + 1);
+                value.setImpossible();
+                value.bound = ValueFlow::Value::Bound::Lower;
+                addToErrorPath(value, diff.maxRef);
+                result.push_back(value);
+            }
+        }
+    } else if ((op == "!=" || op == "==") && lhs.isScalarOrEmpty() && rhs.isScalarOrEmpty()) {
+        if (lhs.isScalar() && rhs.isScalar()) {
+            std::vector<const ValueFlow::Value*> refs = Interval::merge(lhs.getScalarRef(), rhs.getScalarRef());
+            ValueFlow::Value value(calculate(op, lhs.getScalar(), rhs.getScalar()));
+            addToErrorPath(value, refs);
+            setValueKind(value, refs);
+            result.push_back(value);
+        } else {
+            std::vector<const ValueFlow::Value*> refs;
+            if (lhs.isScalar() && inferNotEqual(rhsValues, lhs.getScalar()))
+                refs = lhs.getScalarRef();
+            else if (rhs.isScalar() && inferNotEqual(lhsValues, rhs.getScalar()))
+                refs = rhs.getScalarRef();
+            if (!refs.empty()) {
+                ValueFlow::Value value(op == "!=");
+                addToErrorPath(value, refs);
+                setValueKind(value, refs);
+                result.push_back(value);
+            }
+        }
+    } else {
+        std::vector<const ValueFlow::Value*> refs;
+        std::vector<bool> r = Interval::compare(op, lhs, rhs, &refs);
+        if (!r.empty()) {
+            ValueFlow::Value value(r.front());
+            addToErrorPath(value, refs);
+            setValueKind(value, refs);
+            result.push_back(value);
+        }
+    }
+
+    return result;
+}
+
+std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
+                                    const std::string& op,
+                                    MathLib::bigint lhs,
+                                    std::list<ValueFlow::Value> rhsValues)
+{
+    return infer(model, op, {model->yield(lhs)}, std::move(rhsValues));
+}
+
+std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
+                                    const std::string& op,
+                                    std::list<ValueFlow::Value> lhsValues,
+                                    MathLib::bigint rhs)
+{
+    return infer(model, op, std::move(lhsValues), {model->yield(rhs)});
+}

lib/infer.h

@@ -0,0 +1,52 @@
+/*
+ * Cppcheck - A tool for static C/C++ code analysis
+ * Copyright (C) 2007-2021 Cppcheck team.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef inferH
+#define inferH
+
+#include "mathlib.h"
+#include "valueflow.h"
+
+struct Interval;
+template<class T>
+class ValuePtr;
+
+struct InferModel {
+    virtual bool match(const ValueFlow::Value& value) const = 0;
+    virtual ValueFlow::Value yield(MathLib::bigint value) const = 0;
+    virtual ~InferModel() {}
+};
+
+std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
+                                    const std::string& op,
+                                    std::list<ValueFlow::Value> lhsValues,
+                                    std::list<ValueFlow::Value> rhsValues);
+
+std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
+                                    const std::string& op,
+                                    MathLib::bigint lhs,
+                                    std::list<ValueFlow::Value> rhsValues);
+
+std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
+                                    const std::string& op,
+                                    std::list<ValueFlow::Value> lhsValues,
+                                    MathLib::bigint rhs);
+
+std::string toString(const Interval& i);
+
+#endif

lib/lib.pri

@@ -41,6 +41,7 @@ HEADERS += $${PWD}/analyzerinfo.h \
            $${PWD}/exprengine.h \
            $${PWD}/forwardanalyzer.h \
            $${PWD}/importproject.h \
+           $${PWD}/infer.h \
            $${PWD}/library.h \
            $${PWD}/mathlib.h \
            $${PWD}/path.h \
@@ -100,6 +101,7 @@ SOURCES += $${PWD}/analyzerinfo.cpp \
            $${PWD}/exprengine.cpp \
            $${PWD}/forwardanalyzer.cpp \
            $${PWD}/importproject.cpp \
+           $${PWD}/infer.cpp \
            $${PWD}/library.cpp \
            $${PWD}/mathlib.cpp \
            $${PWD}/path.cpp \

lib/valueflow.cpp

@@ -85,6 +85,7 @@
 #include "errorlogger.h"
 #include "errortypes.h"
 #include "forwardanalyzer.h"
+#include "infer.h"
 #include "library.h"
 #include "mathlib.h"
 #include "path.h"
@@ -4424,322 +4425,6 @@ static void valueFlowSymbolicAbs(TokenList* tokenlist, SymbolDatabase* symboldat
     }
 }
 
-template<class Predicate, class Compare>
-static const ValueFlow::Value* getCompareValue(const std::list<ValueFlow::Value>& values,
-                                               Predicate pred,
-                                               Compare compare)
-{
-    const ValueFlow::Value* result = nullptr;
-    for (const ValueFlow::Value& value : values) {
-        if (!pred(value))
-            continue;
-        if (result)
-            result = &std::min(value, *result, [compare](const ValueFlow::Value& x, const ValueFlow::Value& y) {
-                return compare(x.intvalue, y.intvalue);
-            });
-        else
-            result = &value;
-    }
-    return result;
-}
-
-struct Interval {
-    std::vector<MathLib::bigint> minvalue = {};
-    std::vector<MathLib::bigint> maxvalue = {};
-    std::vector<const ValueFlow::Value*> minRef = {};
-    std::vector<const ValueFlow::Value*> maxRef = {};
-
-    void setMinValue(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
-    {
-        minvalue = {x};
-        if (ref)
-            minRef = {ref};
-    }
-
-    void setMaxValue(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
-    {
-        maxvalue = {x};
-        if (ref)
-            maxRef = {ref};
-    }
-
-    bool isLessThan(MathLib::bigint x, std::vector<const ValueFlow::Value*>* ref = nullptr) const
-    {
-        if (!this->maxvalue.empty() && this->maxvalue.front() < x) {
-            if (ref)
-                *ref = maxRef;
-            return true;
-        }
-        return false;
-    }
-
-    bool isGreaterThan(MathLib::bigint x, std::vector<const ValueFlow::Value*>* ref = nullptr) const
-    {
-        if (!this->minvalue.empty() && this->minvalue.front() > x) {
-            if (ref)
-                *ref = minRef;
-            return true;
-        }
-        return false;
-    }
-
-    bool isScalar() const {
-        return minvalue.size() == 1 && minvalue == maxvalue;
-    }
-
-    bool empty() const {
-        return minvalue.empty() && maxvalue.empty();
-    }
-
-    bool isScalarOrEmpty() const {
-        return empty() || isScalar();
-    }
-
-    MathLib::bigint getScalar() const
-    {
-        assert(isScalar());
-        return minvalue.front();
-    }
-
-    std::vector<const ValueFlow::Value*> getScalarRef() const
-    {
-        assert(isScalar());
-        if (!minRef.empty())
-            return minRef;
-        if (!maxRef.empty())
-            return maxRef;
-        return {};
-    }
-
-    static Interval fromInt(MathLib::bigint x, const ValueFlow::Value* ref = nullptr)
-    {
-        Interval result;
-        result.setMinValue(x, ref);
-        result.setMaxValue(x, ref);
-        return result;
-    }
-
-    template<class Predicate>
-    static Interval fromValues(const std::list<ValueFlow::Value>& values, Predicate predicate)
-    {
-        Interval result;
-        const ValueFlow::Value* minValue = getCompareValue(values, predicate, std::less<MathLib::bigint>{});
-        if (minValue) {
-            if (minValue->isImpossible() && minValue->bound == ValueFlow::Value::Bound::Upper)
-                result.setMinValue(minValue->intvalue + 1, minValue);
-            if (minValue->isPossible() && minValue->bound == ValueFlow::Value::Bound::Lower)
-                result.setMinValue(minValue->intvalue, minValue);
-            if (minValue->isKnown())
-                return Interval::fromInt(minValue->intvalue, minValue);
-        }
-        const ValueFlow::Value* maxValue = getCompareValue(values, predicate, std::greater<MathLib::bigint>{});
-        if (maxValue) {
-            if (maxValue->isImpossible() && maxValue->bound == ValueFlow::Value::Bound::Lower)
-                result.setMaxValue(maxValue->intvalue - 1, maxValue);
-            if (maxValue->isPossible() && maxValue->bound == ValueFlow::Value::Bound::Upper)
-                result.setMaxValue(maxValue->intvalue, maxValue);
-            assert(!maxValue->isKnown());
-        }
-        return result;
-    }
-
-    static Interval fromValues(const std::list<ValueFlow::Value>& values)
-    {
-        return Interval::fromValues(values, [](const ValueFlow::Value&) {
-            return true;
-        });
-    }
-
-    template<class F>
-    static std::vector<MathLib::bigint> apply(const std::vector<MathLib::bigint>& x,
-                                              const std::vector<MathLib::bigint>& y,
-                                              F f)
-    {
-        if (x.empty())
-            return {};
-        if (y.empty())
-            return {};
-        return {f(x.front(), y.front())};
-    }
-
-    static std::vector<const ValueFlow::Value*> merge(std::vector<const ValueFlow::Value*> x,
-                                                      const std::vector<const ValueFlow::Value*>& y)
-    {
-        x.insert(x.end(), y.begin(), y.end());
-        return x;
-    }
-
-    friend Interval operator-(const Interval& lhs, const Interval& rhs)
-    {
-        Interval result;
-        result.minvalue = Interval::apply(lhs.minvalue, rhs.maxvalue, std::minus<MathLib::bigint>{});
-        result.maxvalue = Interval::apply(lhs.maxvalue, rhs.minvalue, std::minus<MathLib::bigint>{});
-        if (!result.minvalue.empty())
-            result.minRef = merge(lhs.minRef, rhs.maxRef);
-        if (!result.maxvalue.empty())
-            result.maxRef = merge(lhs.maxRef, rhs.minRef);
-        return result;
-    }
-
-    static std::vector<int> equal(const Interval& lhs,
-                                  const Interval& rhs,
-                                  std::vector<const ValueFlow::Value*>* ref = nullptr)
-    {
-        if (!lhs.isScalar())
-            return {};
-        if (!rhs.isScalar())
-            return {};
-        if (ref)
-            *ref = merge(lhs.minRef, rhs.minRef);
-        return {lhs.minvalue == rhs.minvalue};
-    }
-
-    static std::vector<int> compare(const Interval& lhs,
-                                    const Interval& rhs,
-                                    std::vector<const ValueFlow::Value*>* ref = nullptr)
-    {
-        Interval diff = lhs - rhs;
-        if (diff.isGreaterThan(0, ref))
-            return {1};
-        if (diff.isLessThan(0, ref))
-            return {-1};
-        std::vector<int> eq = Interval::equal(lhs, rhs, ref);
-        if (!eq.empty() && eq.front() != 0)
-            return {0};
-        return {};
-    }
-};
-
-static void addToErrorPath(ValueFlow::Value& value, const std::vector<const ValueFlow::Value*>& refs)
-{
-    for (const ValueFlow::Value* ref : refs) {
-        value.errorPath.insert(value.errorPath.end(), ref->errorPath.begin(), ref->errorPath.end());
-    }
-}
-
-static void setValueKind(ValueFlow::Value& value, const std::vector<const ValueFlow::Value*>& refs)
-{
-    bool isPossible = false;
-    bool isInconclusive = false;
-    for (const ValueFlow::Value* ref : refs) {
-        if (ref->isPossible())
-            isPossible = true;
-        if (ref->isInconclusive())
-            isInconclusive = true;
-    }
-    if (isInconclusive)
-        value.setInconclusive();
-    else if (isPossible)
-        value.setPossible();
-    else
-        value.setKnown();
-}
-
-struct InferModel {
-    virtual bool match(const ValueFlow::Value& value) const = 0;
-    virtual ValueFlow::Value yield(MathLib::bigint value) const = 0;
-    virtual ~InferModel() {}
-};
-
-static bool inferNotEqual(const std::list<ValueFlow::Value>& values, MathLib::bigint x)
-{
-    return std::any_of(values.begin(), values.end(), [&](const ValueFlow::Value& value) {
-        return value.isImpossible() && value.intvalue == x;
-    });
-}
-
-static std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
-                                           const std::string& op,
-                                           std::list<ValueFlow::Value> lhsValues,
-                                           std::list<ValueFlow::Value> rhsValues)
-{
-    std::vector<ValueFlow::Value> result;
-    auto notMatch = [&](const ValueFlow::Value& value) {
-        return !model->match(value);
-    };
-    lhsValues.remove_if(notMatch);
-    rhsValues.remove_if(notMatch);
-    if (lhsValues.empty() || rhsValues.empty())
-        return result;
-
-    Interval lhs = Interval::fromValues(lhsValues);
-    Interval rhs = Interval::fromValues(rhsValues);
-
-    if (op == "-") {
-        Interval diff = lhs - rhs;
-        if (diff.isScalar()) {
-            std::vector<const ValueFlow::Value*> refs = diff.getScalarRef();
-            ValueFlow::Value value(diff.getScalar());
-            addToErrorPath(value, refs);
-            setValueKind(value, refs);
-            result.push_back(value);
-        } else {
-            if (!diff.minvalue.empty()) {
-                ValueFlow::Value value(diff.minvalue.front() - 1);
-                value.setImpossible();
-                value.bound = ValueFlow::Value::Bound::Upper;
-                addToErrorPath(value, diff.minRef);
-                result.push_back(value);
-            }
-            if (!diff.maxvalue.empty()) {
-                ValueFlow::Value value(diff.maxvalue.front() + 1);
-                value.setImpossible();
-                value.bound = ValueFlow::Value::Bound::Lower;
-                addToErrorPath(value, diff.maxRef);
-                result.push_back(value);
-            }
-        }
-    } else if ((op == "!=" || op == "==") && lhs.isScalarOrEmpty() && rhs.isScalarOrEmpty()) {
-        if (lhs.isScalar() && rhs.isScalar()) {
-            std::vector<const ValueFlow::Value*> refs = Interval::merge(lhs.getScalarRef(), rhs.getScalarRef());
-            ValueFlow::Value value(calculate(op, lhs.getScalar(), rhs.getScalar()));
-            addToErrorPath(value, refs);
-            setValueKind(value, refs);
-            result.push_back(value);
-        } else {
-            std::vector<const ValueFlow::Value*> refs;
-            if (lhs.isScalar() && inferNotEqual(rhsValues, lhs.getScalar()))
-                refs = lhs.getScalarRef();
-            else if (rhs.isScalar() && inferNotEqual(lhsValues, rhs.getScalar()))
-                refs = rhs.getScalarRef();
-            if (!refs.empty()) {
-                ValueFlow::Value value(op == "!=");
-                addToErrorPath(value, refs);
-                setValueKind(value, refs);
-                result.push_back(value);
-            }
-        }
-    } else {
-        std::vector<const ValueFlow::Value*> refs;
-        std::vector<int> r = Interval::compare(lhs, rhs, &refs);
-        if (!r.empty()) {
-            int x = r.front();
-            ValueFlow::Value value(calculate(op, x, 0));
-            addToErrorPath(value, refs);
-            setValueKind(value, refs);
-            result.push_back(value);
-        }
-    }
-
-    return result;
-}
-
-static std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
-                                           const std::string& op,
-                                           MathLib::bigint lhs,
-                                           std::list<ValueFlow::Value> rhsValues)
-{
-    return infer(model, op, {model->yield(lhs)}, std::move(rhsValues));
-}
-
-static std::vector<ValueFlow::Value> infer(const ValuePtr<InferModel>& model,
-                                           const std::string& op,
-                                           std::list<ValueFlow::Value> lhsValues,
-                                           MathLib::bigint rhs)
-{
-    return infer(model, op, std::move(lhsValues), {model->yield(rhs)});
-}
-
 struct SymbolicInferModel : InferModel {
     const Token* expr;
     explicit SymbolicInferModel(const Token* tok) : expr(tok) {
@@ -5543,82 +5228,18 @@ struct SimpleConditionHandler : ConditionHandler {
     }
 };
 
-static bool isInBounds(const ValueFlow::Value& value, MathLib::bigint x)
-{
-    if (value.intvalue == x)
-        return true;
-    if (value.bound == ValueFlow::Value::Bound::Lower && value.intvalue > x)
-        return false;
-    if (value.bound == ValueFlow::Value::Bound::Upper && value.intvalue < x)
-        return false;
-    // Checking for equality is not necessary since we already know the value is not equal
-    if (value.bound == ValueFlow::Value::Bound::Point)
-        return false;
-    return true;
-}
-
-static const ValueFlow::Value* getCompareIntValue(const std::list<ValueFlow::Value>& values, std::function<bool(MathLib::bigint, MathLib::bigint)> compare)
-{
-    const ValueFlow::Value* result = nullptr;
-    for (const ValueFlow::Value& value : values) {
-        if (!value.isIntValue())
-            continue;
-        if (result)
-            result = &std::min(value, *result, [compare](const ValueFlow::Value& x, const ValueFlow::Value& y) {
-                return compare(x.intvalue, y.intvalue);
-            });
-        else
-            result = &value;
+struct IntegralInferModel : InferModel {
+    virtual bool match(const ValueFlow::Value& value) const OVERRIDE {
+        return value.isIntValue();
     }
-    return result;
-}
-
-static const ValueFlow::Value* proveLessThan(const std::list<ValueFlow::Value>& values, MathLib::bigint x)
-{
-    const ValueFlow::Value* result = nullptr;
-    const ValueFlow::Value* maxValue = getCompareIntValue(values, std::greater<MathLib::bigint> {});
-    if (maxValue && maxValue->isImpossible() && maxValue->bound == ValueFlow::Value::Bound::Lower) {
-        if (maxValue->intvalue <= x)
-            result = maxValue;
+    virtual ValueFlow::Value yield(MathLib::bigint value) const OVERRIDE
+    {
+        ValueFlow::Value result(value);
+        result.valueType = ValueFlow::Value::ValueType::INT;
+        result.setKnown();
+        return result;
     }
-    return result;
-}
-
-static const ValueFlow::Value* proveGreaterThan(const std::list<ValueFlow::Value>& values, MathLib::bigint x)
-{
-    const ValueFlow::Value* result = nullptr;
-    const ValueFlow::Value* minValue = getCompareIntValue(values, std::less<MathLib::bigint> {});
-    if (minValue && minValue->isImpossible() && minValue->bound == ValueFlow::Value::Bound::Upper) {
-        if (minValue->intvalue >= x)
-            result = minValue;
-    }
-    return result;
-}
-
-static const ValueFlow::Value* proveNotEqual(const std::list<ValueFlow::Value>& values, MathLib::bigint x)
-{
-    const ValueFlow::Value* result = nullptr;
-    for (const ValueFlow::Value& value : values) {
-        if (value.valueType != ValueFlow::Value::ValueType::INT)
-            continue;
-        if (result && !isInBounds(value, result->intvalue))
-            continue;
-        if (value.isImpossible()) {
-            if (value.intvalue == x)
-                return &value;
-            if (!isInBounds(value, x))
-                continue;
-            result = &value;
-        } else {
-            if (value.intvalue == x)
-                return nullptr;
-            if (!isInBounds(value, x))
-                continue;
-            result = nullptr;
-        }
-    }
-    return result;
-}
+};
 
 ValueFlow::Value inferCondition(const std::string& op, const Token* varTok, MathLib::bigint val)
 {
@@ -5626,52 +5247,22 @@ ValueFlow::Value inferCondition(const std::string& op, const Token* varTok, Math
         return ValueFlow::Value{};
     if (varTok->hasKnownIntValue())
         return ValueFlow::Value{};
-    if (std::none_of(varTok->values().begin(), varTok->values().end(), [](const ValueFlow::Value& v) {
-        return v.isImpossible() && v.valueType == ValueFlow::Value::ValueType::INT;
-    })) {
-        return ValueFlow::Value{};
-    }
-    const ValueFlow::Value* result = nullptr;
-    bool known = false;
-    if (op == "==" || op == "!=") {
-        result = proveNotEqual(varTok->values(), val);
-        known = op == "!=";
-    } else if (op == "<" || op == ">=") {
-        result = proveLessThan(varTok->values(), val);
-        known = op == "<";
-        if (!result && !isSaturated(val)) {
-            result = proveGreaterThan(varTok->values(), val - 1);
-            known = op == ">=";
-        }
-    } else if (op == ">" || op == "<=") {
-        result = proveGreaterThan(varTok->values(), val);
-        known = op == ">";
-        if (!result && !isSaturated(val)) {
-            result = proveLessThan(varTok->values(), val + 1);
-            known = op == "<=";
-        }
-    }
-    if (!result)
-        return ValueFlow::Value{};
-    ValueFlow::Value value = *result;
-    value.intvalue = known;
-    value.bound = ValueFlow::Value::Bound::Point;
-    value.setKnown();
-    return value;
+    std::vector<ValueFlow::Value> r = infer(IntegralInferModel{}, op, varTok->values(), val);
+    if (r.size() == 1 && r.front().isKnown())
+        return r.front();
+    return ValueFlow::Value{};
 }
 
 ValueFlow::Value inferCondition(std::string op, MathLib::bigint val, const Token* varTok)
 {
-    // Flip the operator
-    if (op == ">")
-        op = "<";
-    else if (op == "<")
-        op = ">";
-    else if (op == ">=")
-        op = "<=";
-    else if (op == "<=")
-        op = ">=";
-    return inferCondition(op, varTok, val);
+    if (!varTok)
+        return ValueFlow::Value{};
+    if (varTok->hasKnownIntValue())
+        return ValueFlow::Value{};
+    std::vector<ValueFlow::Value> r = infer(IntegralInferModel{}, op, val, varTok->values());
+    if (r.size() == 1 && r.front().isKnown())
+        return r.front();
+    return ValueFlow::Value{};
 }
 
 static void valueFlowInferCondition(TokenList* tokenlist,
@@ -5684,30 +5275,20 @@ static void valueFlowInferCondition(TokenList* tokenlist,
             continue;
         if (tok->variable() && (Token::Match(tok->astParent(), "?|&&|!|%oror%") ||
                                 Token::Match(tok->astParent()->previous(), "if|while ("))) {
-            const ValueFlow::Value* result = proveNotEqual(tok->values(), 0);
-            if (!result)
+            std::vector<ValueFlow::Value> result = infer(IntegralInferModel{}, "!=", tok->values(), 0);
+            if (result.size() != 1)
                 continue;
-            ValueFlow::Value value = *result;
+            ValueFlow::Value value = result.front();
             value.intvalue = 1;
             value.bound = ValueFlow::Value::Bound::Point;
             value.setKnown();
             setTokenValue(tok, value, settings);
-        } else if (tok->isComparisonOp()) {
-            ValueFlow::Value value{};
-            std::string op = tok->str();
-            if (tok->astOperand1()->hasKnownIntValue()) {
-                MathLib::bigint val = tok->astOperand1()->values().front().intvalue;
-                const Token* varTok = tok->astOperand2();
-                value = inferCondition(tok->str(), val, varTok);
-            } else if (tok->astOperand2()->hasKnownIntValue()) {
-                MathLib::bigint val = tok->astOperand2()->values().front().intvalue;
-                const Token* varTok = tok->astOperand1();
-                value = inferCondition(tok->str(), varTok, val);
+        } else if (Token::Match(tok, "%comp%|-") && tok->astOperand1() && tok->astOperand2()) {
+            std::vector<ValueFlow::Value> result =
+                infer(IntegralInferModel{}, tok->str(), tok->astOperand1()->values(), tok->astOperand2()->values());
+            for (const ValueFlow::Value& value : result) {
+                setTokenValue(tok, value, settings);
             }
-
-            if (!value.isKnown())
-                continue;
-            setTokenValue(tok, value, settings);
         }
     }
 }

test/testcondition.cpp

@@ -954,7 +954,7 @@ private:
               "    }\n"
               "    return false;\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:2]: (style) Condition 'c!=a' is always false\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:2]: (style) Condition 'c!=a' is always false\n", errout.str());
     }
 
     void incorrectLogicOperator2() {
@@ -3330,7 +3330,7 @@ private:
               "    if (handle) return 1;\n"
               "    else return 0;\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Condition 'handle' is always true\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:3]: (style) Condition 'handle' is always true\n", errout.str());
 
         check("int f(void *handle) {\n"
               "    if (handle != 0) return 0;\n"
@@ -3393,7 +3393,7 @@ private:
               "        if(array){}\n"
               "    }\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:5]: (style) Condition 'array' is always true\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:5]: (style) Condition 'array' is always true\n", errout.str());
 
         check("void f(int *array, int size ) {\n"
               "    for(int i = 0; i < size; ++i) {\n"
@@ -3402,7 +3402,7 @@ private:
               "        else if(array){}\n"
               "    }\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:5]: (style) Condition 'array' is always true\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:5]: (style) Condition 'array' is always true\n", errout.str());
 
         // #9277
         check("int f() {\n"
@@ -3770,7 +3770,7 @@ private:
         check("void f(int i) {\n"
               "    if(i < 0 && abs(i) == i) {}\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:2]: (style) Condition 'abs(i)==i' is always false\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:2]: (style) Condition 'abs(i)==i' is always false\n", errout.str());
 
         check("void f(int i) {\n"
               "    if(i > -3 && abs(i) == i) {}\n"
@@ -3810,7 +3810,7 @@ private:
               "        if(x == y) {}\n"
               "    }\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (style) Condition 'x==y' is always false\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:4]: (style) Condition 'x==y' is always false\n", errout.str());
 
         check("void f(bool a, bool b) {  if (a == b && a && !b){} }");
         ASSERT_EQUALS("[test.cpp:1] -> [test.cpp:1]: (style) Condition '!b' is always false\n", errout.str());
@@ -3824,7 +3824,7 @@ private:
               "    if (z < 1) {}\n"
               "  }\n"
               "}\n");
-        ASSERT_EQUALS("[test.cpp:4]: (style) Condition 'z<1' is always false\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:4]: (style) Condition 'z<1' is always false\n", errout.str());
 
         check("struct a {\n"
               "  a *b() const;\n"
@@ -4002,6 +4002,13 @@ private:
               "        if(i<=18) {}\n"
               "}\n");
         ASSERT_EQUALS("[test.cpp:3]: (style) Condition 'i<=18' is always true\n", errout.str());
+
+        check("void f(unsigned int u1, unsigned int u2) {\n"
+              "    if (u1 <= 10 && u2 >= 20) {\n"
+              "        if (u1 != u2) {}\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Condition 'u1!=u2' is always true\n", errout.str());
     }
 
     void alwaysTrueContainer() {