diff --git a/configure.ac b/configure.ac
index 83e026227..f10564938 100644
--- a/configure.ac
+++ b/configure.ac
@@ -302,7 +302,6 @@ AC_SUBST(CFG_CXXFLAGS_WEXTRA)
 _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_SRC,-Qunused-arguments)
 _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_SRC,-faligned-new)
 _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_SRC,-Wno-unused-parameter)
-_MY_CXX_CHECK_OPT(CFG_CXXFLAGS_SRC,-Wno-undefined-bool-conversion)
 _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_SRC,-Wno-shadow)
 AC_SUBST(CFG_CXXFLAGS_SRC)
 
diff --git a/include/verilated.cpp b/include/verilated.cpp
index c24a3b2d7..373082276 100644
--- a/include/verilated.cpp
+++ b/include/verilated.cpp
@@ -884,7 +884,7 @@ static inline int  _vl_vsss_peek(FILE* fp, int& floc, WDataInP fromp,
 }
 static inline void _vl_vsss_skipspace(FILE* fp, int& floc,
                                       WDataInP fromp, const std::string& fstr) VL_MT_SAFE {
-    while (1) {
+    while (true) {
         int c = _vl_vsss_peek(fp, floc, fromp, fstr);
         if (c==EOF || !isspace(c)) return;
         _vl_vsss_advance(fp, floc);
@@ -894,7 +894,7 @@ static inline void _vl_vsss_read(FILE* fp, int& floc, WDataInP fromp, const std:
                                  char* tmpp, const char* acceptp) VL_MT_SAFE {
     // Read into tmp, consisting of characters from acceptp list
     char* cp = tmpp;
-    while (1) {
+    while (true) {
         int c = _vl_vsss_peek(fp, floc, fromp, fstr);
         if (c==EOF || isspace(c)) break;
         if (acceptp  // String - allow anything
@@ -1340,7 +1340,7 @@ IData VL_FREAD_I(int width, int array_lsb, int array_size,
     // Read the data
     // We process a character at a time, as then we don't need to deal
     // with changing buffer sizes dynamically, etc.
-    while (1) {
+    while (true) {
         int c = fgetc(fp);
         if (VL_UNLIKELY(c == EOF)) break;
         // Shift value in
@@ -1668,7 +1668,7 @@ bool VlReadMem::get(QData& addrr, std::string& valuer) {
     // Read the data
     // We process a character at a time, as then we don't need to deal
     // with changing buffer sizes dynamically, etc.
-    while (1) {
+    while (true) {
         int c = fgetc(m_fp);
         if (VL_UNLIKELY(c == EOF)) break;
         // printf("%d: Got '%c' Addr%lx IN%d IgE%d IgC%d\n",
@@ -1853,7 +1853,7 @@ void VL_READMEM_N(bool hex,  // Hex format, else binary
 
     VlReadMem rmem(hex, bits, filename, start, end);
     if (VL_UNLIKELY(!rmem.isOpen())) return;
-    while (1) {
+    while (true) {
         QData addr;
         std::string value;
         if (rmem.get(addr /*ref*/, value/*ref*/)) {
@@ -2183,9 +2183,7 @@ void VerilatedImp::commandArgsAddGuts(int argc, const char** argv) VL_REQUIRES(s
 void VerilatedImp::commandArgVl(const std::string& arg) {
     if (0 == strncmp(arg.c_str(), "+verilator+", strlen("+verilator+"))) {
         std::string value;
-        if (0) {
-        }
-        else if (arg == "+verilator+debug") {
+        if (arg == "+verilator+debug") {
             Verilated::debug(4);
         }
         else if (commandArgVlValue(arg, "+verilator+debugi+", value/*ref*/)) {
diff --git a/include/verilated.h b/include/verilated.h
index fdd921ea7..2aed894a1 100644
--- a/include/verilated.h
+++ b/include/verilated.h
@@ -316,7 +316,7 @@ private:
 public:  // But internals only - called from VerilatedModule's
     VerilatedScope();
     ~VerilatedScope();
-    void configure(VerilatedSyms* symsp, const char* prefixp, const char* suffix,
+    void configure(VerilatedSyms* symsp, const char* prefixp, const char* suffixp,
                    const char* identifier, const Type type) VL_MT_UNSAFE;
     void exportInsert(int finalize, const char* namep, void* cb) VL_MT_UNSAFE;
     void varInsert(int finalize, const char* namep, void* datap,
@@ -1653,18 +1653,22 @@ static inline void _VL_INSERT_WW(int, WDataOutP owp, WDataInP lwp, int hbit, int
                 int oword = lword+i;
                 EData d = lwp[i] << loffset;
                 EData od = (owp[oword] & ~linsmask) | (d & linsmask);
-                if (oword == hword)
+                if (oword == hword) {
                     owp[oword] = (owp[oword] & ~hinsmask) | (od & hinsmask);
-                else owp[oword] = od;
+                } else {
+                    owp[oword] = od;
+                }
             }
             {   // Upper word
                 int oword = lword+i+1;
                 if (oword <= hword) {
                     EData d = lwp[i] >> nbitsonright;
                     EData od = (d & ~linsmask) | (owp[oword] & linsmask);
-                    if (oword == hword)
+                    if (oword == hword) {
                         owp[oword] = (owp[oword] & ~hinsmask) | (od & hinsmask);
-                    else owp[oword] = od;
+                    } else {
+                        owp[oword] = od;
+                    }
                 }
             }
         }
@@ -2280,7 +2284,6 @@ static inline WDataOutP VL_RTOIROUND_W_D(int obits, WDataOutP owp, double lhs) V
     if (lsb < 0) {
         VL_SET_WQ(owp, mantissa >> -lsb);
     } else if (lsb < obits) {
-        int lsbword = VL_BITWORD_I(lsb);
         _VL_INSERT_WQ(obits, owp, mantissa, lsb + 52, lsb);
     }
     if (lhs < 0) VL_NEGATE_INPLACE_W(VL_WORDS_I(obits), owp);
diff --git a/include/verilated_cov.cpp b/include/verilated_cov.cpp
index 4dafaf1bb..24f83dd8f 100644
--- a/include/verilated_cov.cpp
+++ b/include/verilated_cov.cpp
@@ -74,7 +74,7 @@ public:
     virtual void zero() const VL_OVERRIDE { *m_countp = 0; }
     // CONSTRUCTORS
     // cppcheck-suppress noExplicitConstructor
-    VerilatedCoverItemSpec(T* countp) : m_countp(countp) { *m_countp = 0; }
+    explicit VerilatedCoverItemSpec(T* countp) : m_countp(countp) { *m_countp = 0; }
     virtual ~VerilatedCoverItemSpec() VL_OVERRIDE {}
 };
 
diff --git a/include/verilated_cov.h b/include/verilated_cov.h
index 3b8c22634..5aa11a2d7 100644
--- a/include/verilated_cov.h
+++ b/include/verilated_cov.h
@@ -29,9 +29,15 @@
 /// Conditionally compile coverage code
 
 #ifdef VM_COVERAGE
-# define VL_IF_COVER(stmts) do { stmts ; } while(0)
+# define VL_IF_COVER(stmts) \
+    do { \
+        stmts; \
+    } while (false)
 #else
-# define VL_IF_COVER(stmts) do { if(0) { stmts ; } } while(0)
+# define VL_IF_COVER(stmts) \
+    do { \
+        if (false) { stmts; } \
+    } while (false)
 #endif
 
 //=============================================================================
diff --git a/include/verilated_heavy.h b/include/verilated_heavy.h
index 0fec46946..774450707 100644
--- a/include/verilated_heavy.h
+++ b/include/verilated_heavy.h
@@ -33,10 +33,10 @@
 //===================================================================
 // String formatters (required by below containers)
 
-extern std::string VL_TO_STRING(CData obj);
-extern std::string VL_TO_STRING(SData obj);
-extern std::string VL_TO_STRING(IData obj);
-extern std::string VL_TO_STRING(QData obj);
+extern std::string VL_TO_STRING(CData lhs);
+extern std::string VL_TO_STRING(SData lhs);
+extern std::string VL_TO_STRING(IData lhs);
+extern std::string VL_TO_STRING(QData lhs);
 inline std::string VL_TO_STRING(const std::string& obj) { return "\"" + obj + "\""; }
 extern std::string VL_TO_STRING_W(int words, WDataInP obj);
 
@@ -158,7 +158,7 @@ public:
     int next(T_Key& indexr) const {
         typename Map::const_iterator it = m_map.find(indexr);
         if (VL_UNLIKELY(it == m_map.end())) return 0;
-        it++;
+        ++it;
         if (VL_UNLIKELY(it == m_map.end())) return 0;
         indexr = it->first;
         return 1;
@@ -217,7 +217,7 @@ void VL_READMEM_N(bool hex, int bits, const std::string& filename,
                   VlAssocArray<T_Key, T_Value>& obj, QData start, QData end) VL_MT_SAFE {
     VlReadMem rmem(hex, bits, filename, start, end);
     if (VL_UNLIKELY(!rmem.isOpen())) return;
-    while (1) {
+    while (true) {
         QData addr;
         std::string data;
         if (rmem.get(addr /*ref*/, data /*ref*/)) {
diff --git a/include/verilated_save.cpp b/include/verilated_save.cpp
index 516d2d872..18b668e98 100644
--- a/include/verilated_save.cpp
+++ b/include/verilated_save.cpp
@@ -184,7 +184,7 @@ void VerilatedSave::flush() VL_MT_UNSAFE_ONE {
     m_assertOne.check();
     if (VL_UNLIKELY(!isOpen())) return;
     vluint8_t* wp = m_bufp;
-    while (1) {
+    while (true) {
         ssize_t remaining = (m_cp - wp);
         if (remaining==0) break;
         errno = 0;
@@ -213,7 +213,7 @@ void VerilatedRestore::fill() VL_MT_UNSAFE_ONE {
     m_endp = m_bufp + (m_endp - m_cp);
     m_cp = m_bufp;  // Reset buffer
     // Read into buffer starting at m_endp
-    while (1) {
+    while (true) {
         ssize_t remaining = (m_bufp+bufferSize() - m_endp);
         if (remaining==0) break;
         errno = 0;
diff --git a/include/verilated_threads.cpp b/include/verilated_threads.cpp
index 3734a48b0..7568e1585 100644
--- a/include/verilated_threads.cpp
+++ b/include/verilated_threads.cpp
@@ -36,7 +36,8 @@ VlMTaskVertex::VlMTaskVertex(vluint32_t upstreamDepCount)
 // VlWorkerThread
 
 VlWorkerThread::VlWorkerThread(VlThreadPool* poolp, bool profiling)
-    : m_ready_size(0)
+    : m_waiting(false)
+    , m_ready_size(0)
     , m_poolp(poolp)
     , m_profiling(profiling)
     , m_exiting(false)
@@ -58,7 +59,7 @@ void VlWorkerThread::workerLoop() {
     ExecRec work;
     work.m_fnp = NULL;
 
-    while (1) {
+    while (true) {
         if (VL_LIKELY(!work.m_fnp)) {
             dequeWork(&work);
         }
diff --git a/include/verilated_unordered_set_map.h b/include/verilated_unordered_set_map.h
index 86982f3d8..9800b39a1 100644
--- a/include/verilated_unordered_set_map.h
+++ b/include/verilated_unordered_set_map.h
@@ -147,7 +147,7 @@ public:
             return (!this->operator==(other));
         }
         void advanceUntilValid() {
-            while (1) {
+            while (true) {
                 if (m_bit != m_setp->m_bucketsp[m_bucketIdx].end()) {
                     // Valid iterator in this bucket; we're done.
                     return;
diff --git a/include/verilated_vcd_c.cpp b/include/verilated_vcd_c.cpp
index d263f45db..bf344ecc9 100644
--- a/include/verilated_vcd_c.cpp
+++ b/include/verilated_vcd_c.cpp
@@ -364,7 +364,7 @@ void VerilatedVcd::bufferFlush() VL_MT_UNSAFE_ONE {
     m_assertOne.check();
     if (VL_UNLIKELY(!isOpen())) return;
     char* wp = m_wrBufp;
-    while (1) {
+    while (true) {
         ssize_t remaining = (m_writep - wp);
         if (remaining==0) break;
         errno = 0;
diff --git a/include/verilated_vpi.cpp b/include/verilated_vpi.cpp
index f76e75894..2a6f727df 100644
--- a/include/verilated_vpi.cpp
+++ b/include/verilated_vpi.cpp
@@ -76,21 +76,22 @@ public:
         if (VL_UNCOVERABLE(size>chunk)) VL_FATAL_MT(__FILE__, __LINE__, "", "increase chunk");
         if (VL_LIKELY(t_freeHead)) {
             vluint8_t* newp = t_freeHead;
-            t_freeHead = *((vluint8_t**)newp);
+            t_freeHead = *(reinterpret_cast<vluint8_t**>(newp));
             return newp+8;
         }
         // +8: 8 bytes for next
         vluint8_t* newp = reinterpret_cast<vluint8_t*>(::operator new(chunk+8));
         return newp+8;
     }
-    inline static void operator delete(void* obj, size_t size) VL_MT_SAFE {
-        vluint8_t* oldp = ((vluint8_t*)obj)-8;
-        *((void**)oldp) = t_freeHead;
+    inline static void operator delete(void* obj, size_t /*size*/)VL_MT_SAFE {
+        vluint8_t* oldp = (static_cast<vluint8_t*>(obj)) - 8;
+        *(reinterpret_cast<void**>(oldp)) = t_freeHead;
         t_freeHead = oldp;
     }
     // MEMBERS
     static inline VerilatedVpio* castp(vpiHandle h) {
-        return dynamic_cast<VerilatedVpio*>((VerilatedVpio*)h); }
+        return dynamic_cast<VerilatedVpio*>(reinterpret_cast<VerilatedVpio*>(h));
+    }
     inline vpiHandle castVpiHandle() { return reinterpret_cast<vpiHandle>(this); }
     // ACCESSORS
     virtual const char* name() const { return "<null>"; }
@@ -117,7 +118,8 @@ public:
     }
     virtual ~VerilatedVpioCb() {}
     static inline VerilatedVpioCb* castp(vpiHandle h) {
-        return dynamic_cast<VerilatedVpioCb*>((VerilatedVpio*)h); }
+        return dynamic_cast<VerilatedVpioCb*>(reinterpret_cast<VerilatedVpio*>(h));
+    }
     virtual vluint32_t type() const { return vpiCallback; }
     vluint32_t reason() const { return m_cbData.reason; }
     VerilatedPliCb cb_rtnp() const { return m_cbData.cb_rtn; }
@@ -131,7 +133,8 @@ public:
     explicit VerilatedVpioConst(vlsint32_t num) : m_num(num) {}
     virtual ~VerilatedVpioConst() {}
     static inline VerilatedVpioConst* castp(vpiHandle h) {
-        return dynamic_cast<VerilatedVpioConst*>((VerilatedVpio*)h); }
+        return dynamic_cast<VerilatedVpioConst*>(reinterpret_cast<VerilatedVpio*>(h));
+    }
     virtual vluint32_t type() const { return vpiUndefined; }
     vlsint32_t num() const { return m_num; }
 };
@@ -143,7 +146,8 @@ public:
     explicit VerilatedVpioRange(const VerilatedRange* range) : m_range(range), m_iteration(0) {}
     virtual ~VerilatedVpioRange() {}
     static inline VerilatedVpioRange* castp(vpiHandle h) {
-        return dynamic_cast<VerilatedVpioRange*>((VerilatedVpio*)h); }
+        return dynamic_cast<VerilatedVpioRange*>(reinterpret_cast<VerilatedVpio*>(h));
+    }
     virtual vluint32_t type() const { return vpiRange; }
     virtual vluint32_t size() const { return m_range->elements(); }
     virtual const VerilatedRange* rangep() const { return m_range; }
@@ -167,7 +171,8 @@ public:
         : m_scopep(scopep) {}
     virtual ~VerilatedVpioScope() {}
     static inline VerilatedVpioScope* castp(vpiHandle h) {
-        return dynamic_cast<VerilatedVpioScope*>((VerilatedVpio*)h); }
+        return dynamic_cast<VerilatedVpioScope*>(reinterpret_cast<VerilatedVpio*>(h));
+    }
     virtual vluint32_t type() const { return vpiScope; }
     const VerilatedScope* scopep() const { return m_scopep; }
     virtual const char* name() const { return m_scopep->name(); }
@@ -202,7 +207,8 @@ public:
         if (m_prevDatap) { delete [] m_prevDatap; m_prevDatap = NULL; }
     }
     static inline VerilatedVpioVar* castp(vpiHandle h) {
-        return dynamic_cast<VerilatedVpioVar*>((VerilatedVpio*)h); }
+        return dynamic_cast<VerilatedVpioVar*>(reinterpret_cast<VerilatedVpio*>(h));
+    }
     const VerilatedVar* varp() const { return m_varp; }
     const VerilatedScope* scopep() const { return m_scopep; }
     vluint32_t mask() const { return m_mask.u32; }
@@ -236,11 +242,12 @@ public:
                             vlsint32_t index, int offset)
         : VerilatedVpioVar(varp, scopep) {
         m_index = index;
-        m_varDatap = ((vluint8_t*)varp->datap()) + entSize()*offset;
+        m_varDatap = (static_cast<vluint8_t*>(varp->datap())) + entSize() * offset;
     }
     virtual ~VerilatedVpioMemoryWord() {}
     static inline VerilatedVpioMemoryWord* castp(vpiHandle h) {
-        return dynamic_cast<VerilatedVpioMemoryWord*>((VerilatedVpio*)h); }
+        return dynamic_cast<VerilatedVpioMemoryWord*>(reinterpret_cast<VerilatedVpio*>(h));
+    }
     virtual vluint32_t type() const { return vpiMemoryWord; }
     virtual  vluint32_t size() const { return varp()->packed().elements(); }
     virtual const VerilatedRange* rangep() const { return &(varp()->packed()); }
@@ -261,7 +268,8 @@ public:
         : m_scopep(scopep), m_started(false) {  }
     virtual ~VerilatedVpioVarIter() {}
     static inline VerilatedVpioVarIter* castp(vpiHandle h) {
-        return dynamic_cast<VerilatedVpioVarIter*>((VerilatedVpio*)h); }
+        return dynamic_cast<VerilatedVpioVarIter*>(reinterpret_cast<VerilatedVpio*>(h));
+    }
     virtual vluint32_t type() const { return vpiIterator; }
     virtual vpiHandle dovpi_scan() {
         if (VL_LIKELY(m_scopep->varsp())) {
@@ -291,7 +299,8 @@ public:
           m_done(false) { }
     virtual ~VerilatedVpioMemoryWordIter() {}
     static inline VerilatedVpioMemoryWordIter* castp(vpiHandle h) {
-        return dynamic_cast<VerilatedVpioMemoryWordIter*>((VerilatedVpio*)h); }
+        return dynamic_cast<VerilatedVpioMemoryWordIter*>(reinterpret_cast<VerilatedVpio*>(h));
+    }
     virtual vluint32_t type() const { return vpiIterator; }
     void iterationInc() {
         if (!(m_done = (m_iteration == m_varp->unpacked().left()))) {
@@ -318,7 +327,8 @@ public:
         m_name = m_scopep->identifier();
     }
     static inline VerilatedVpioModule* castp(vpiHandle h) {
-        return dynamic_cast<VerilatedVpioModule*>((VerilatedVpio*)h); }
+        return dynamic_cast<VerilatedVpioModule*>(reinterpret_cast<VerilatedVpio*>(h));
+    }
     virtual vluint32_t type() const { return vpiModule; }
     virtual const char* name() const { return m_name; }
     virtual const char* fullname() const { return m_fullname; }
@@ -333,7 +343,8 @@ public:
     }
     virtual ~VerilatedVpioModuleIter() {}
     static inline VerilatedVpioModuleIter* castp(vpiHandle h) {
-        return dynamic_cast<VerilatedVpioModuleIter*>((VerilatedVpio*) h); }
+        return dynamic_cast<VerilatedVpioModuleIter*>(reinterpret_cast<VerilatedVpio*>(h));
+    }
     virtual vluint32_t type() const { return vpiIterator; }
     virtual vpiHandle dovpi_scan() {
         if (m_it == m_vec->end()) {
@@ -461,7 +472,7 @@ public:
                                             varop->fullname(),
                                             *((CData*)newDatap), *((CData*)prevDatap),
                                             newDatap, prevDatap););
-                if (memcmp(prevDatap, newDatap, varop->entSize())) {
+                if (memcmp(prevDatap, newDatap, varop->entSize()) != 0) {
                     VL_DEBUG_IF_PLI(VL_DBG_MSGF("- vpi: value_callback %p %s v[0]=%d\n",
                                                 vop, varop->fullname(), *((CData*)newDatap)););
                     update.insert(varop);
@@ -505,7 +516,7 @@ public:
 
     VerilatedVpiError() : m_flag(false) {
         m_buff[0] = '\0';
-        m_errorInfo.product = (PLI_BYTE8*)Verilated::productName();
+        m_errorInfo.product = const_cast<PLI_BYTE8*>(Verilated::productName());
     }
     ~VerilatedVpiError() {}
     static void selfTest() VL_MT_UNSAFE_ONE;
@@ -514,7 +525,7 @@ public:
         m_errorInfo.level = level;
         return this;
     }
-    void setMessage(std::string file, PLI_INT32 line, const char* message, ...) {
+    void setMessage(const std::string& file, PLI_INT32 line, const char* message, ...) {
         // message cannot be a const string& as va_start cannot use a reference
         static VL_THREAD_LOCAL std::string filehold;
         va_list args;
@@ -523,7 +534,7 @@ public:
         va_end(args);
         m_errorInfo.state = vpiPLI;
         filehold = file;
-        setError((PLI_BYTE8*)m_buff, NULL, (PLI_BYTE8*)filehold.c_str(), line);
+        setError((PLI_BYTE8*)m_buff, NULL, const_cast<PLI_BYTE8*>(filehold.c_str()), line);
     }
     p_vpi_error_info getError() {
         if (m_flag) return &m_errorInfo;
@@ -1024,14 +1035,13 @@ PLI_INT32 vpi_remove_cb(vpiHandle object) {
     return 1;
 }
 
-void vpi_get_cb_info(vpiHandle object, p_cb_data cb_data_p) {
-    _VL_VPI_UNIMP(); return;
+void vpi_get_cb_info(vpiHandle /*object*/, p_cb_data /*cb_data_p*/) { _VL_VPI_UNIMP(); }
+vpiHandle vpi_register_systf(p_vpi_systf_data /*systf_data_p*/) {
+    _VL_VPI_UNIMP();
+    return 0;
 }
-vpiHandle vpi_register_systf(p_vpi_systf_data systf_data_p) {
-    _VL_VPI_UNIMP(); return 0;
-}
-void vpi_get_systf_info(vpiHandle object, p_vpi_systf_data systf_data_p) {
-    _VL_VPI_UNIMP(); return;
+void vpi_get_systf_info(vpiHandle /*object*/, p_vpi_systf_data /*systf_data_p*/) {
+    _VL_VPI_UNIMP();
 }
 
 // for obtaining handles
@@ -1047,7 +1057,7 @@ vpiHandle vpi_handle_by_name(PLI_BYTE8* namep, vpiHandle scope) {
     std::string scopeAndName = namep;
     if (voScopep) {
         scopeAndName = std::string(voScopep->fullname()) + "." + namep;
-        namep = (PLI_BYTE8*)scopeAndName.c_str();
+        namep = const_cast<PLI_BYTE8*>(scopeAndName.c_str());
     }
     {
         // This doesn't yet follow the hierarchy in the proper way
@@ -1067,7 +1077,7 @@ vpiHandle vpi_handle_by_name(PLI_BYTE8* namep, vpiHandle scope) {
             scopename = std::string(namep, dotp-namep);
         }
 
-        if (scopename.find(".") == std::string::npos) {
+        if (scopename.find('.') == std::string::npos) {
             // This is a toplevel, hence search in our TOP ports first.
             scopep = Verilated::scopeFind("TOP");
             if (scopep) {
@@ -1150,8 +1160,10 @@ vpiHandle vpi_handle(PLI_INT32 type, vpiHandle object) {
     }
 }
 
-vpiHandle vpi_handle_multi(PLI_INT32 type, vpiHandle refHandle1, vpiHandle refHandle2, ... ) {
-    _VL_VPI_UNIMP(); return 0;
+vpiHandle vpi_handle_multi(PLI_INT32 /*type*/, vpiHandle /*refHandle1*/, vpiHandle /*refHandle2*/,
+                           ...) {
+    _VL_VPI_UNIMP();
+    return 0;
 }
 
 vpiHandle vpi_iterate(PLI_INT32 type, vpiHandle object) {
@@ -1194,7 +1206,7 @@ vpiHandle vpi_iterate(PLI_INT32 type, vpiHandle object) {
         VerilatedVpioModule* vop = VerilatedVpioModule::castp(object);
         const VerilatedHierarchyMap* map = VerilatedImp::hierarchyMap();
         const VerilatedScope *mod = vop ? vop->scopep() : NULL;
-        VerilatedHierarchyMap::const_iterator it = map->find((VerilatedScope*) mod);
+        VerilatedHierarchyMap::const_iterator it = map->find(const_cast<VerilatedScope*>(mod));
         if (it == map->end()) return 0;
         return  ((new VerilatedVpioModuleIter(it->second))->castVpiHandle());
     }
@@ -1256,7 +1268,7 @@ PLI_INT32 vpi_get(PLI_INT32 property, vpiHandle object) {
     }
 }
 
-PLI_INT64 vpi_get64(PLI_INT32 property, vpiHandle object) {
+PLI_INT64 vpi_get64(PLI_INT32 /*property*/, vpiHandle /*object*/) {
     _VL_VPI_UNIMP();
     return 0;
 }
@@ -1269,16 +1281,16 @@ PLI_BYTE8 *vpi_get_str(PLI_INT32 property, vpiHandle object) {
     if (VL_UNLIKELY(!vop)) return NULL;
     switch (property) {
     case vpiName: {
-        return (PLI_BYTE8*)vop->name();
+        return const_cast<PLI_BYTE8*>(vop->name());
     }
     case vpiFullName: {
-        return (PLI_BYTE8*)vop->fullname();
+        return const_cast<PLI_BYTE8*>(vop->fullname());
     }
     case vpiDefName: {
-        return (PLI_BYTE8*)vop->defname();
+        return const_cast<PLI_BYTE8*>(vop->defname());
     }
     case vpiType: {
-        return (PLI_BYTE8*) VerilatedVpiError::strFromVpiObjType(vop->type());
+        return const_cast<PLI_BYTE8*>(VerilatedVpiError::strFromVpiObjType(vop->type()));
     }
     default:
         _VL_VPI_WARNING(__FILE__, __LINE__, "%s: Unsupported type %s, nothing will be returned",
@@ -1289,14 +1301,8 @@ PLI_BYTE8 *vpi_get_str(PLI_INT32 property, vpiHandle object) {
 
 // delay processing
 
-void vpi_get_delays(vpiHandle object, p_vpi_delay delay_p) {
-    _VL_VPI_UNIMP();
-    return;
-}
-void vpi_put_delays(vpiHandle object, p_vpi_delay delay_p) {
-    _VL_VPI_UNIMP();
-    return;
-}
+void vpi_get_delays(vpiHandle /*object*/, p_vpi_delay /*delay_p*/) { _VL_VPI_UNIMP(); }
+void vpi_put_delays(vpiHandle /*object*/, p_vpi_delay /*delay_p*/) { _VL_VPI_UNIMP(); }
 
 // value processing
 
@@ -1582,8 +1588,8 @@ void vpi_get_value(vpiHandle object, p_vpi_value value_p) {
                   VL_FUNC, VerilatedVpiError::strFromVpiVal(value_p->format));
 }
 
-vpiHandle vpi_put_value(vpiHandle object, p_vpi_value value_p,
-                        p_vpi_time time_p, PLI_INT32 flags) {
+vpiHandle vpi_put_value(vpiHandle object, p_vpi_value value_p, p_vpi_time /*time_p*/,
+                        PLI_INT32 /*flags*/) {
     VL_DEBUG_IF_PLI(VL_DBG_MSGF("- vpi: vpi_put_value %p %p\n", object, value_p););
     VerilatedVpiImp::assertOneCheck();
     _VL_VPI_ERROR_RESET();
@@ -1876,19 +1882,18 @@ vpiHandle vpi_put_value(vpiHandle object, p_vpi_value value_p,
     return NULL;
 }
 
-void vpi_get_value_array(vpiHandle object, p_vpi_arrayvalue arrayvalue_p,
-                                       PLI_INT32 *index_p, PLI_UINT32 num) {
-    _VL_VPI_UNIMP(); return;
+void vpi_get_value_array(vpiHandle /*object*/, p_vpi_arrayvalue /*arrayvalue_p*/,
+                         PLI_INT32* /*index_p*/, PLI_UINT32 /*num*/) {
+    _VL_VPI_UNIMP();
 }
-void vpi_put_value_array(vpiHandle object, p_vpi_arrayvalue arrayvalue_p,
-                                       PLI_INT32 *index_p, PLI_UINT32 num) {
-    _VL_VPI_UNIMP(); return;
+void vpi_put_value_array(vpiHandle /*object*/, p_vpi_arrayvalue /*arrayvalue_p*/,
+                         PLI_INT32* /*index_p*/, PLI_UINT32 /*num*/) {
+    _VL_VPI_UNIMP();
 }
 
-
 // time processing
 
-void vpi_get_time(vpiHandle object, p_vpi_time time_p) {
+void vpi_get_time(vpiHandle /*object*/, p_vpi_time time_p) {
     VerilatedVpiImp::assertOneCheck();
     // cppcheck-suppress nullPointer
     if (VL_UNLIKELY(!time_p)) {
@@ -1905,7 +1910,6 @@ void vpi_get_time(vpiHandle object, p_vpi_time time_p) {
     }
     _VL_VPI_ERROR(__FILE__, __LINE__, "%s: Unsupported type (%d)",
                   VL_FUNC, time_p->type);
-    return;
 }
 
 // I/O routines
@@ -1919,11 +1923,13 @@ PLI_UINT32 vpi_mcd_open(PLI_BYTE8 *filenamep) {
 PLI_UINT32 vpi_mcd_close(PLI_UINT32 mcd) {
     VerilatedVpiImp::assertOneCheck();
     _VL_VPI_ERROR_RESET();
-    VL_FCLOSE_I(mcd); return 0;
+    VL_FCLOSE_I(mcd);
+    return 0;
 }
 
-PLI_BYTE8 *vpi_mcd_name(PLI_UINT32 mcd) {
-    _VL_VPI_UNIMP(); return 0;
+PLI_BYTE8* vpi_mcd_name(PLI_UINT32 /*mcd*/) {
+    _VL_VPI_UNIMP();
+    return 0;
 }
 
 PLI_INT32 vpi_mcd_printf(PLI_UINT32 mcd, PLI_BYTE8 *formatp, ...) {
@@ -1980,8 +1986,9 @@ PLI_INT32 vpi_mcd_flush(PLI_UINT32 mcd) {
 
 // utility routines
 
-PLI_INT32 vpi_compare_objects(vpiHandle object1, vpiHandle object2) {
-    _VL_VPI_UNIMP(); return 0;
+PLI_INT32 vpi_compare_objects(vpiHandle /*object1*/, vpiHandle /*object2*/) {
+    _VL_VPI_UNIMP();
+    return 0;
 }
 PLI_INT32 vpi_chk_error(p_vpi_error_info error_info_p) {
     // executing vpi_chk_error does not reset error
@@ -2016,25 +2023,29 @@ PLI_INT32 vpi_get_vlog_info(p_vpi_vlog_info vlog_info_p) VL_MT_SAFE {
     VerilatedVpiImp::assertOneCheck();
     _VL_VPI_ERROR_RESET();
     vlog_info_p->argc = Verilated::getCommandArgs()->argc;
-    vlog_info_p->argv = (PLI_BYTE8**)Verilated::getCommandArgs()->argv;
-    vlog_info_p->product = (PLI_BYTE8*)Verilated::productName();
-    vlog_info_p->version = (PLI_BYTE8*)Verilated::productVersion();
+    vlog_info_p->argv = const_cast<PLI_BYTE8**>(Verilated::getCommandArgs()->argv);
+    vlog_info_p->product = const_cast<PLI_BYTE8*>(Verilated::productName());
+    vlog_info_p->version = const_cast<PLI_BYTE8*>(Verilated::productVersion());
     return 1;
 }
 
 // routines added with 1364-2001
 
-PLI_INT32 vpi_get_data(PLI_INT32 id, PLI_BYTE8 *dataLoc, PLI_INT32 numOfBytes) {
-    _VL_VPI_UNIMP(); return 0;
+PLI_INT32 vpi_get_data(PLI_INT32 /*id*/, PLI_BYTE8* /*dataLoc*/, PLI_INT32 /*numOfBytes*/) {
+    _VL_VPI_UNIMP();
+    return 0;
 }
-PLI_INT32 vpi_put_data(PLI_INT32 id, PLI_BYTE8 *dataLoc, PLI_INT32 numOfBytes) {
-    _VL_VPI_UNIMP(); return 0;
+PLI_INT32 vpi_put_data(PLI_INT32 /*id*/, PLI_BYTE8* /*dataLoc*/, PLI_INT32 /*numOfBytes*/) {
+    _VL_VPI_UNIMP();
+    return 0;
 }
-void *vpi_get_userdata(vpiHandle obj) {
-    _VL_VPI_UNIMP(); return 0;
+void* vpi_get_userdata(vpiHandle /*obj*/) {
+    _VL_VPI_UNIMP();
+    return 0;
 }
-PLI_INT32 vpi_put_userdata(vpiHandle obj, void *userdata) {
-    _VL_VPI_UNIMP(); return 0;
+PLI_INT32 vpi_put_userdata(vpiHandle /*obj*/, void* /*userdata*/) {
+    _VL_VPI_UNIMP();
+    return 0;
 }
 
 PLI_INT32 vpi_control(PLI_INT32 operation, ...) {
@@ -2056,6 +2067,8 @@ PLI_INT32 vpi_control(PLI_INT32 operation, ...) {
     return 0;
 }
 
-vpiHandle vpi_handle_by_multi_index(vpiHandle obj, PLI_INT32 num_index, PLI_INT32 *index_array) {
-    _VL_VPI_UNIMP(); return 0;
+vpiHandle vpi_handle_by_multi_index(vpiHandle /*obj*/, PLI_INT32 /*num_index*/,
+                                    PLI_INT32* /*index_array*/) {
+    _VL_VPI_UNIMP();
+    return 0;
 }
diff --git a/include/verilatedos.h b/include/verilatedos.h
index f46da01b4..4bbfa0fe3 100644
--- a/include/verilatedos.h
+++ b/include/verilatedos.h
@@ -153,15 +153,32 @@
 # define VL_DANGLING(var)
 #else
 ///< After e.g. delete, set variable to NULL to indicate must not use later
-# define VL_DANGLING(var) do { (var) = NULL; } while(0)
+# define VL_DANGLING(var) \
+    do { \
+        (var) = NULL; \
+    } while (false)
 #endif
 
 ///< Perform an e.g. delete, then set variable to NULL to indicate must not use later.
 ///< Unlike VL_DO_CLEAR the setting of the variable is only for debug reasons.
-#define VL_DO_DANGLING(stmt, var) do { do { stmt; } while(0); VL_DANGLING(var); } while(0)
+#define VL_DO_DANGLING(stmt, var) \
+    do { \
+        do { \
+            stmt; \
+        } while (false); \
+        VL_DANGLING(var); \
+    } while (false)
 
 ///< Perform an e.g. delete, then set variable to NULL as a requirement
-#define VL_DO_CLEAR(stmt, stmt2) do { do { stmt; } while(0); do { stmt2; } while(0); } while(0)
+#define VL_DO_CLEAR(stmt, stmt2) \
+    do { \
+        do { \
+            stmt; \
+        } while (false); \
+        do { \
+            stmt2; \
+        } while (false); \
+    } while (false)
 
 //=========================================================================
 // C++-2011
diff --git a/src/V3Active.cpp b/src/V3Active.cpp
index 2dee3a6f3..0aad9730c 100644
--- a/src/V3Active.cpp
+++ b/src/V3Active.cpp
@@ -415,15 +415,14 @@ private:
     virtual void visit(AstNodeMath* nodep) VL_OVERRIDE {}
     virtual void visit(AstVarScope* nodep) VL_OVERRIDE {}
     //--------------------
-    virtual void visit(AstNode* nodep) VL_OVERRIDE {
-        iterateChildren(nodep);
-    }
+    virtual void visit(AstNode* nodep) VL_OVERRIDE { iterateChildren(nodep); }
+
 public:
     // CONSTRUCTORS
-    explicit ActiveVisitor(AstNetlist* nodep) {
-        m_scopeFinalp = NULL;
-        m_itemCombo = false;
-        m_itemSequent = false;
+    explicit ActiveVisitor(AstNetlist* nodep)
+        : m_scopeFinalp(NULL)
+        , m_itemCombo(false)
+        , m_itemSequent(false) {
         iterate(nodep);
     }
     virtual ~ActiveVisitor() {}
diff --git a/src/V3ActiveTop.cpp b/src/V3ActiveTop.cpp
index 4c486f3ed..6adf1a893 100644
--- a/src/V3ActiveTop.cpp
+++ b/src/V3ActiveTop.cpp
@@ -131,13 +131,12 @@ private:
     virtual void visit(AstNodeMath* nodep) VL_OVERRIDE {}
     virtual void visit(AstVarScope* nodep) VL_OVERRIDE {}
     //--------------------
-    virtual void visit(AstNode* nodep) VL_OVERRIDE {
-        iterateChildren(nodep);
-    }
+    virtual void visit(AstNode* nodep) VL_OVERRIDE { iterateChildren(nodep); }
+
 public:
     // CONSTRUCTORS
-    explicit ActiveTopVisitor(AstNetlist* nodep) {
-        m_topscopep = NULL;
+    explicit ActiveTopVisitor(AstNetlist* nodep)
+        : m_topscopep(NULL) {
         iterate(nodep);
     }
     virtual ~ActiveTopVisitor() {}
diff --git a/src/V3Ast.cpp b/src/V3Ast.cpp
index 962e4f6d0..42ac68911 100644
--- a/src/V3Ast.cpp
+++ b/src/V3Ast.cpp
@@ -1204,7 +1204,7 @@ AstNodeDType* AstNode::findLogicDType(int width, int widthMin, AstNumeric numeri
     return v3Global.rootp()->typeTablep()
         ->findLogicBitDType(fileline(), AstBasicDTypeKwd::LOGIC, width, widthMin, numeric);
 }
-AstNodeDType* AstNode::findLogicRangeDType(VNumRange range, int widthMin,
+AstNodeDType* AstNode::findLogicRangeDType(const VNumRange& range, int widthMin,
                                            AstNumeric numeric) const {
     return v3Global.rootp()->typeTablep()
         ->findLogicBitDType(fileline(), AstBasicDTypeKwd::LOGIC, range, widthMin, numeric);
diff --git a/src/V3Ast.h b/src/V3Ast.h
index 71fe67c5c..edc5ca021 100644
--- a/src/V3Ast.h
+++ b/src/V3Ast.h
@@ -50,13 +50,13 @@ typedef std::set<int> MTaskIdSet;  // Set of mtaskIds for Var sorting
 #define BROKEN_RTN(test) \
     do { \
         if (VL_UNCOVERABLE(test)) return #test; \
-    } while (0)
+    } while (false)
 // For broken() function, return error string if a base of this class has a match
 #define BROKEN_BASE_RTN(test) \
     do { \
         const char* reasonp = (test); \
         if (VL_UNCOVERABLE(reasonp)) return reasonp; \
-    } while (0)
+    } while (false)
 
 // (V)erilator (N)ode is: True if AstNode is of a a given AstType
 #define VN_IS(nodep,nodetypename) (AstNode::privateIs<Ast ## nodetypename>(nodep))
@@ -1559,7 +1559,8 @@ public:
     AstNodeDType* findVoidDType() const;
     AstNodeDType* findBitDType(int width, int widthMin, AstNumeric numeric) const;
     AstNodeDType* findLogicDType(int width, int widthMin, AstNumeric numeric) const;
-    AstNodeDType* findLogicRangeDType(VNumRange range, int widthMin, AstNumeric numeric) const;
+    AstNodeDType* findLogicRangeDType(const VNumRange& range, int widthMin,
+                                      AstNumeric numeric) const;
     AstNodeDType* findBasicDType(AstBasicDTypeKwd kwd) const;
     AstBasicDType* findInsertSameDType(AstBasicDType* nodep);
 
diff --git a/src/V3Cdc.cpp b/src/V3Cdc.cpp
index 179c51bdf..a5c306464 100644
--- a/src/V3Cdc.cpp
+++ b/src/V3Cdc.cpp
@@ -502,7 +502,7 @@ private:
         for (V3GraphVertex* itp = m_graph.verticesBeginp(); itp; itp=itp->verticesNextp()) {
             if (CdcVarVertex* vvertexp = dynamic_cast<CdcVarVertex*>(itp)) {
                 AstVar* varp = vvertexp->varScp()->varp();
-                if (1) {  // varp->isPrimaryIO()
+                {
                     string what = "wire";
                     if (varp->isPrimaryIO()) what = varp->direction().prettyName();
 
@@ -752,11 +752,11 @@ public:
 
         iterate(nodep);
         analyze();
-        if (debug()>=1) edgeReport();  // Not useful to users at the moment
-        if (0) {
-            *m_ofp<<"\nDBG-test-dumper\n";
+        if (debug() >= 1) edgeReport();  // Not useful to users at the moment
+        if (false) {
+            *m_ofp << "\nDBG-test-dumper\n";
             V3EmitV::verilogPrefixedTree(nodep, *m_ofp, "DBG ", 40, NULL, true);
-            *m_ofp<<endl;
+            *m_ofp << endl;
         }
     }
     virtual ~CdcVisitor() {
diff --git a/src/V3Const.cpp b/src/V3Const.cpp
index b7588acf8..8e92b861d 100644
--- a/src/V3Const.cpp
+++ b/src/V3Const.cpp
@@ -592,15 +592,12 @@ private:
         bool rad = ifMergeAdjacent(lp->rhsp(), rp->rhsp());
         if (lad && rad) return true;
         // {a[] & b[]&c[], a[] & b[]&c[]}
-        else if (lad && concatMergeable(lp->rhsp(), rp->rhsp())) return true;
+        if (lad && concatMergeable(lp->rhsp(), rp->rhsp())) return true;
         // {a[]&b[] & c[], a[]&b[] & c[]}
-        else if (rad && concatMergeable(lp->lhsp(), rp->lhsp())) return true;
-        else {
-            // {(a[]&b[])&(c[]&d[]), (a[]&b[])&(c[]&d[])}
-            if (concatMergeable(lp->lhsp(), rp->lhsp())
-                && concatMergeable(lp->rhsp(), rp->rhsp()))
-                return true;
-        }
+        if (rad && concatMergeable(lp->lhsp(), rp->lhsp())) return true;
+        // {(a[]&b[])&(c[]&d[]), (a[]&b[])&(c[]&d[])}
+        if (concatMergeable(lp->lhsp(), rp->lhsp())
+            && concatMergeable(lp->rhsp(), rp->rhsp())) return true;
         return false;
     }
 
diff --git a/src/V3CoverageJoin.cpp b/src/V3CoverageJoin.cpp
index 088f46c13..6ef96c206 100644
--- a/src/V3CoverageJoin.cpp
+++ b/src/V3CoverageJoin.cpp
@@ -68,7 +68,7 @@ private:
                 // Want to choose a base node, and keep finding duplicates that are identical.
                 // This prevents making chains where a->b, then c->d, then b->c, as we'll
                 // find a->b, a->c, a->d directly.
-                while (1) {
+                while (true) {
                     V3Hashed::iterator dupit = hashed.findDuplicate(nodep->origp());
                     if (dupit == hashed.end()) break;
                     //
diff --git a/src/V3EmitCMake.cpp b/src/V3EmitCMake.cpp
index b58885803..2eed8feb8 100644
--- a/src/V3EmitCMake.cpp
+++ b/src/V3EmitCMake.cpp
@@ -70,12 +70,11 @@ class CMakeEmitter {
         cmake_set_raw(of, name, raw_value, cache_type, docstring);
     }
 
-    //Swap all backslashes for forward slashes, because of Windows
+    // Swap all backslashes for forward slashes, because of Windows
     static string deslash(const string& s) {
         std::string res = s;
         for (string::iterator it = res.begin(); it != res.end(); ++it) {
-            if (*it == '\\')
-                *it = '/';
+            if (*it == '\\') *it = '/';
         }
         return res;
     }
diff --git a/src/V3EmitCSyms.cpp b/src/V3EmitCSyms.cpp
index 157d18b77..6fcba2ef9 100644
--- a/src/V3EmitCSyms.cpp
+++ b/src/V3EmitCSyms.cpp
@@ -141,7 +141,7 @@ class EmitCSyms : EmitCBaseVisitor {
     string scopeDecodeIdentifier(const string& scpname) {
         string out = scpname;
         // Remove hierarchy
-        string::size_type  pos = out.rfind(".");
+        string::size_type pos = out.rfind('.');
         if (pos != std::string::npos) out.erase(0, pos + 1);
         // Decode all escaped characters
         while ((pos = out.find("__0")) != string::npos) {
@@ -163,10 +163,8 @@ class EmitCSyms : EmitCBaseVisitor {
             }
             string::size_type pos = scp.rfind("__DOT__");
             if (pos == string::npos) {
-                pos = scp.rfind(".");
-                if (pos == string::npos) {
-                    break;
-                }
+                pos = scp.rfind('.');
+                if (pos == string::npos) break;
             }
             scp.resize(pos);
         }
@@ -228,10 +226,8 @@ class EmitCSyms : EmitCBaseVisitor {
 
             string above = name;
             while (!above.empty()) {
-                string::size_type pos = above.rfind(".");
-                if (pos == string::npos) {
-                    break;
-                }
+                string::size_type pos = above.rfind('.');
+                if (pos == string::npos) break;
                 above.resize(pos);
                 if (m_vpiScopeHierarchy.find(above) != m_vpiScopeHierarchy.end()) {
                     m_vpiScopeHierarchy[above].push_back(name);
@@ -671,8 +667,8 @@ void EmitCSyms::emitSymImp() {
             string name = it->second.m_prettyName;
             if (it->first == "TOP") continue;
             name = name.replace(0, 4, "");  // Remove the "TOP."
-            if ((name.find(".") == string::npos) && (it->second.m_type == "SCOPE_MODULE")) {
-                puts("__Vhier.add(0, &"+protect("__Vscope_"+it->second.m_symName)+");\n");
+            if ((name.find('.') == string::npos) && (it->second.m_type == "SCOPE_MODULE")) {
+                puts("__Vhier.add(0, &" + protect("__Vscope_" + it->second.m_symName) + ");\n");
             }
         }
 
diff --git a/src/V3EmitV.cpp b/src/V3EmitV.cpp
index df895c31f..7cd2a7be6 100644
--- a/src/V3EmitV.cpp
+++ b/src/V3EmitV.cpp
@@ -740,7 +740,7 @@ public:
 
 void V3EmitV::emitv() {
     UINFO(2,__FUNCTION__<<": "<<endl);
-    if (1) {
+    if (true) {
         // All-in-one file
         V3OutVFile of (v3Global.opt.makeDir()+"/"+v3Global.opt.prefix()+"__Vout.v");
         of.putsHeader();
diff --git a/src/V3Error.h b/src/V3Error.h
index 21a25567e..b6d17b768 100644
--- a/src/V3Error.h
+++ b/src/V3Error.h
@@ -320,31 +320,36 @@ inline void v3errorEndFatal(std::ostringstream& sstr) {
     { if (VL_UNCOVERABLE(debug() >= (level))) { cout << stmsg; } }
 
 #ifdef VL_DEBUG
-# define UDEBUGONLY(stmts) {stmts}
+# define UDEBUGONLY(stmts) \
+    { stmts }
 #else
-# define UDEBUGONLY(stmts) {if (0) {stmts}}
+# define UDEBUGONLY(stmts) \
+    { if (false) { stmts } }
 #endif
 
 // Assertion without object, generally UOBJASSERT preferred
 #define UASSERT(condition,stmsg) \
-    do { if (VL_UNCOVERABLE(!(condition))) { v3fatalSrc(stmsg); }} while(0)
+    do { if (VL_UNCOVERABLE(!(condition))) { v3fatalSrc(stmsg); }} while (false)
 // Assertion with object
 #define UASSERT_OBJ(condition,obj,stmsg) \
-    do { if (VL_UNCOVERABLE(!(condition))) { (obj)->v3fatalSrc(stmsg); }} while(0)
+    do { if (VL_UNCOVERABLE(!(condition))) { (obj)->v3fatalSrc(stmsg); }} while (false)
 // For use in V3Ast static functions only
 #define UASSERT_STATIC(condition,stmsg) \
     do { if (VL_UNCOVERABLE(!(condition))) { \
             std::cerr<<"Internal Error: "<<__FILE__<<":"<<std::dec<<__LINE__ \
-                     <<":"<<(stmsg)<<std::endl; abort(); } } while(0)
+                     <<":"<<(stmsg)<<std::endl; abort(); } } while (false)
 // Check self test values for expected value.  Safe from side-effects.
 // Type argument can be removed when go to C++11 (use auto).
 #define UASSERT_SELFTEST(Type,got,exp) \
     do { Type g = (got); Type e = (exp); \
          UASSERT(g==e, "Self-test failed '" #got "==" #exp "'"" got=" \
-                 <<g<<" expected="<<e); } while(0)
+                 <<g<<" expected="<<e); } while(false)
 
 #define V3ERROR_NA \
-    do { v3error("Internal: Unexpected Call"); v3fatalSrc("Unexpected Call"); } while(0)
+    do { \
+        v3error("Internal: Unexpected Call"); \
+        v3fatalSrc("Unexpected Call"); \
+    } while (false)
 
 /// Declare a convenience debug() routine that may be added to any class in
 /// Verilator so that --debugi-<srcfile> will work to control UINFOs in
diff --git a/src/V3File.cpp b/src/V3File.cpp
index 8bfe92542..8a0ae3e08 100644
--- a/src/V3File.cpp
+++ b/src/V3File.cpp
@@ -1024,10 +1024,10 @@ public:
         string out;
         string::size_type start = 0;
         // space, ., ->
-        while (1) {
+        while (true) {
             // When C++11, use find_if and lambda
             string::size_type pos = string::npos;
-            string separator = "";
+            string separator;
             trySep(old, start, " ", pos/*ref*/, separator/*ref*/);
             trySep(old, start, ".", pos/*ref*/, separator/*ref*/);
             trySep(old, start, "->", pos/*ref*/, separator/*ref*/);
diff --git a/src/V3FileLine.cpp b/src/V3FileLine.cpp
index e06a9b727..60984003b 100644
--- a/src/V3FileLine.cpp
+++ b/src/V3FileLine.cpp
@@ -99,8 +99,8 @@ void VFileContent::pushText(const string& text) {
 
     // Insert line-by-line
     string::size_type line_start = 0;
-    while (1) {
-        string::size_type line_end = leftover.find("\n", line_start);
+    while (true) {
+        string::size_type line_end = leftover.find('\n', line_start);
         if (line_end != string::npos) {
             string oneline (leftover, line_start, line_end-line_start+1);
             m_lines.push_back(oneline);  // Keeps newline
@@ -338,17 +338,17 @@ void FileLine::modifyStateInherit(const FileLine* fromp) {
     }
 }
 
-void FileLine::v3errorEnd(std::ostringstream& str, const string& locationStr) {
+void FileLine::v3errorEnd(std::ostringstream& sstr, const string& locationStr) {
     std::ostringstream nsstr;
     if (lastLineno()) nsstr<<this;
-    nsstr<<str.str();
-    nsstr<<endl;
+    nsstr << sstr.str();
+    nsstr << endl;
     std::ostringstream lstr;
     if (!locationStr.empty()) {
         lstr<<std::setw(ascii().length())<<" "<<": "<<locationStr;
     }
     if (warnIsOff(V3Error::errorCode())
-        || V3Config::waive(this, V3Error::errorCode(), str.str())) {
+        || V3Config::waive(this, V3Error::errorCode(), sstr.str())) {
         V3Error::suppressThisWarning();
     }
     else if (!V3Error::errorContexted()) nsstr<<warnContextPrimary();
@@ -393,7 +393,7 @@ string FileLine::prettySource() const {
 string FileLine::warnContext(bool secondary) const {
     V3Error::errorContexted(true);
     if (!v3Global.opt.context()) return "";
-    string out = "";
+    string out;
     if (firstLineno() == lastLineno() && firstColumn()) {
         string sourceLine = prettySource();
         // Don't show super-long lines as can fill screen and unlikely to help user
@@ -451,7 +451,7 @@ void FileLine::deleteAllRemaining() {
     // FileLines are allocated, but never nicely freed, as it's much faster
     // that way.  Unfortunately this makes our leak checking a big mess, so
     // only when leak checking we'll track them all and cleanup.
-    while (1) {
+    while (true) {
         FileLineCheckSet::iterator it = fileLineLeakChecks.begin();
         if (it==fileLineLeakChecks.end()) break;
         delete *it;
diff --git a/src/V3Gate.cpp b/src/V3Gate.cpp
index 613ef7c4a..e88aad42a 100644
--- a/src/V3Gate.cpp
+++ b/src/V3Gate.cpp
@@ -215,17 +215,13 @@ private:
             if (m_lhsVarRef) clearSimple(">1 lhs varRefs");
             m_lhsVarRef = nodep;
         } else {
-            if (m_rhsVarRefs.size()>1) {
+            if (m_rhsVarRefs.size() > 1) {
                 AstNodeVarRef* lastRefp = m_rhsVarRefs.back();
-                if (0) {  // Disable the multiple-input optimization
-                    clearSimple(">1 rhs varRefs");
-                } else {
-                    if (m_buffersOnly) clearSimple(">1 rhs varRefs");
-                    if (!nodep->varScopep()->varp()->gateMultiInputOptimizable()
-                        // We didn't check multiInput on the first varref, so check it here
-                        || !lastRefp->varScopep()->varp()->gateMultiInputOptimizable()) {
-                        clearSimple("!gateMultiInputOptimizable");
-                    }
+                if (m_buffersOnly) clearSimple(">1 rhs varRefs");
+                if (!nodep->varScopep()->varp()->gateMultiInputOptimizable()
+                    // We didn't check multiInput on the first varref, so check it here
+                    || !lastRefp->varScopep()->varp()->gateMultiInputOptimizable()) {
+                    clearSimple("!gateMultiInputOptimizable");
                 }
             }
             m_rhsVarRefs.push_back(nodep);
@@ -565,7 +561,7 @@ void GateVisitor::optimizeSignals(bool allowMultiIn) {
                     && !vvertexp->varScp()->varp()->valuep()
                     && !vvertexp->varScp()->varp()->isSigPublic()) {
                     UINFO(4, "No drivers "<<vvertexp->varScp()<<endl);
-                    if (0) {
+                    if (false) {
                         // If we warned here after constant propagation, what the user considered
                         // reasonable logic may have disappeared.  Issuing a warning would
                         // thus be confusing.  V3Undriven now handles this.
diff --git a/src/V3LinkDot.cpp b/src/V3LinkDot.cpp
index e786acfdf..c6c99006b 100644
--- a/src/V3LinkDot.cpp
+++ b/src/V3LinkDot.cpp
@@ -501,7 +501,7 @@ public:
                  it!=m_scopeAliasMap[samn].end(); ++it) {
                 VSymEnt* lhsp = it->first;
                 VSymEnt* srcp = lhsp;
-                while (1) {  // Follow chain of aliases up to highest level non-alias
+                while (true) {  // Follow chain of aliases up to highest level non-alias
                     ScopeAliasMap::iterator it2 = m_scopeAliasMap[samn].find(srcp);
                     if (it2 != m_scopeAliasMap[samn].end()) { srcp = it2->second; continue; }
                     else break;
diff --git a/src/V3List.h b/src/V3List.h
index 6d01573ac..755fc7426 100644
--- a/src/V3List.h
+++ b/src/V3List.h
@@ -68,8 +68,8 @@ public:
     ~V3ListEnt() {
 #ifdef VL_DEBUG
         // Load bogus pointers so we can catch deletion bugs
-        m_nextp = (T)1;
-        m_prevp = (T)1;
+        m_nextp = reinterpret_cast<T>(1);
+        m_prevp = reinterpret_cast<T>(1);
 #endif
     }
     T nextp() const { return m_nextp; }
diff --git a/src/V3Number.cpp b/src/V3Number.cpp
index ef9e66d8b..ca092ef53 100644
--- a/src/V3Number.cpp
+++ b/src/V3Number.cpp
@@ -1638,7 +1638,7 @@ V3Number& V3Number::opMul(const V3Number& lhs, const V3Number& rhs) {
                 vluint64_t mul = static_cast<vluint64_t>(lhs.m_value[lword])
                     * static_cast<vluint64_t>(rhs.m_value[rword]);
                 for (int qword=lword+rword; qword<this->words(); qword++) {
-                    mul += (vluint64_t)(m_value[qword]);
+                    mul += static_cast<vluint64_t>(m_value[qword]);
                     m_value[qword] = (mul & VL_ULL(0xffffffff));
                     mul = (mul >> VL_ULL(32)) & VL_ULL(0xffffffff);
                 }
diff --git a/src/V3Options.cpp b/src/V3Options.cpp
index fada4f9a6..ebfc8a94b 100644
--- a/src/V3Options.cpp
+++ b/src/V3Options.cpp
@@ -656,10 +656,10 @@ bool V3Options::onoff(const char* sw, const char* arg, bool& flag) {
     else if (0==strncmp(sw, "-no-", 4) && (0==strcmp(sw+4, arg+1))) { flag = false; return true; }
     return false;
 }
-bool V3Options::onoffb(const char* sw, const char* arg, VOptionBool& bflag) {
+bool V3Options::onoffb(const char* sw, const char* arg, VOptionBool& flagr) {
     bool flag;
-    if (onoff(sw, arg, flag/*ref*/)) {
-        bflag.setTrueOrFalse(flag);
+    if (onoff(sw, arg, flag /*ref*/)) {
+        flagr.setTrueOrFalse(flag);
         return true;
     } else {
         return false;
@@ -727,9 +727,8 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc, char
             // Allow gnu -- switches
             if (sw[0]=='-' && sw[1]=='-') ++sw;
             bool hadSwitchPart1 = true;
-            if (0) {}
             // Single switches
-            else if (!strcmp(sw, "-E"))                         { m_preprocOnly = true; }
+            if (!strcmp(sw, "-E"))                              { m_preprocOnly = true; }
             else if ( onoffb(sw, "-MMD", bflag/*ref*/))         { m_makeDepend = bflag; }
             else if ( onoff (sw, "-MP", flag/*ref*/))           { m_makePhony = flag; }
             else if (!strcmp(sw, "-P"))                         { m_preprocNoLine = true; }
diff --git a/src/V3Options.h b/src/V3Options.h
index f7c6586be..890395aba 100644
--- a/src/V3Options.h
+++ b/src/V3Options.h
@@ -77,6 +77,7 @@ public:
         FST,
         FST_THREAD
     } m_e;
+    // cppcheck-suppress noExplicitConstructor
     inline TraceFormat(en _e = VCD) : m_e(_e) {}
     explicit inline TraceFormat(int _e) : m_e(static_cast<en>(_e)) {}
     operator en() const { return m_e; }
@@ -280,7 +281,7 @@ class V3Options {
     void showVersion(bool verbose);
     void coverage(bool flag) { m_coverageLine = m_coverageToggle = m_coverageUser = flag; }
     bool onoff(const char* sw, const char* arg, bool& flag);
-    bool onoffb(const char* sw, const char* arg, VOptionBool& flag);
+    bool onoffb(const char* sw, const char* arg, VOptionBool& flagr);
     bool suffixed(const string& sw, const char* arg);
     string parseFileArg(const string& optdir, const string& relfilename);
     bool parseLangExt(const char* swp, const char* langswp, const V3LangCode& lc);
diff --git a/src/V3Partition.cpp b/src/V3Partition.cpp
index 87fe840f0..9bc836a4f 100644
--- a/src/V3Partition.cpp
+++ b/src/V3Partition.cpp
@@ -726,7 +726,7 @@ public:
                  lit != mtaskp->vertexListp()->end(); ++lit) {
                 const OrderLogicVertex* logicp = (*lit)->logicp();
                 if (!logicp) continue;
-                if (0) {
+                if (false) {
                     // Show nodes only
                     *osp<<"> "; logicp->nodep()->dumpTree(*osp);
                 } else {
@@ -1191,7 +1191,7 @@ public:
 
         doRescore();  // Set initial scores in scoreboard
 
-        while (1) {
+        while (true) {
             // This is the best edge to merge, with the lowest
             // score (shortest local critical path)
             MergeCandidate* mergeCanp = const_cast<MergeCandidate*>(m_sb.bestp());
diff --git a/src/V3PreLex.h b/src/V3PreLex.h
index 55a9973ad..6e51c46a5 100644
--- a/src/V3PreLex.h
+++ b/src/V3PreLex.h
@@ -194,8 +194,13 @@ class V3PreLex {
     void curFilelinep(FileLine* fl) { curStreamp()->m_curFilelinep = fl; }
     void appendDefValue(const char* textp, size_t len) { m_defValue.append(textp, len); }
     void lineDirective(const char* textp);
-    void linenoInc() { if (curStreamp()->m_ignNewlines) curStreamp()->m_ignNewlines--;
-        else curFilelinep()->linenoInc(); }
+    void linenoInc() {
+        if (curStreamp()->m_ignNewlines) {
+            curStreamp()->m_ignNewlines--;
+        } else {
+            curFilelinep()->linenoInc();
+        }
+    }
     void warnBackslashSpace();
     // Called by V3PreProc.cpp to inform lexer
     void pushStateDefArg(int level);
diff --git a/src/V3PreProc.cpp b/src/V3PreProc.cpp
index 0aa73fe00..3328363e4 100644
--- a/src/V3PreProc.cpp
+++ b/src/V3PreProc.cpp
@@ -861,7 +861,7 @@ void V3PreProcImp::candidateDefines(VSpellCheck* spellerp) {
 
 int V3PreProcImp::getRawToken() {
     // Get a token from the file, whatever it may be.
-    while (1) {
+    while (true) {
       next_tok:
         if (m_lineAdd) {
             m_lineAdd--;
@@ -942,7 +942,7 @@ void V3PreProcImp::debugToken(int tok, const char* cmtp) {
 
 int V3PreProcImp::getStateToken() {
     // Return the next state-determined token
-    while (1) {
+    while (true) {
       next_tok:
         if (isEof()) return VP_EOF;
         int tok = getRawToken();
diff --git a/src/V3Scoreboard.h b/src/V3Scoreboard.h
index 968204b6c..4ad378437 100644
--- a/src/V3Scoreboard.h
+++ b/src/V3Scoreboard.h
@@ -501,6 +501,6 @@ private:
 
 namespace V3ScoreboardBase {
     void selfTest();
-}
+}  // namespace V3ScoreboardBase
 
 #endif  // Guard
diff --git a/src/V3Simulate.h b/src/V3Simulate.h
index 817a65eab..ca09d8615 100644
--- a/src/V3Simulate.h
+++ b/src/V3Simulate.h
@@ -851,7 +851,7 @@ private:
         } else if (optimizable()) {
             int loops = 0;
             iterateAndNextNull(nodep->initsp());
-            while (1) {
+            while (true) {
                 UINFO(5, "    FOR-ITER "<<nodep<<endl);
                 iterateAndNextNull(nodep->condp());
                 if (!optimizable()) break;
@@ -880,7 +880,7 @@ private:
             iterateChildren(nodep);
         } else if (optimizable()) {
             int loops = 0;
-            while (1) {
+            while (true) {
                 UINFO(5, "    WHILE-ITER "<<nodep<<endl);
                 iterateAndNextNull(nodep->precondsp());
                 if (jumpingOver(nodep)) break;
diff --git a/src/V3String.cpp b/src/V3String.cpp
index 46cbdbf92..63f3f1f1b 100644
--- a/src/V3String.cpp
+++ b/src/V3String.cpp
@@ -75,7 +75,7 @@ bool VString::wildmatch(const string& s, const string& p) {
 }
 
 bool VString::isWildcard(const string &p) {
-    return ((p.find("*") != string::npos) || (p.find("?") != string::npos));
+    return ((p.find('*') != string::npos) || (p.find('?') != string::npos));
 }
 
 string VString::dot(const string& a, const string& dot, const string& b) {
@@ -144,8 +144,8 @@ static inline uint32_t shaRotr32(uint32_t lhs, uint32_t rhs) {
     return lhs >> rhs | lhs << (32 - rhs);
 }
 
-static inline void sha256Block(uint32_t* h, uint32_t* chunk) VL_ATTR_ALWINLINE;
-static inline void sha256Block(uint32_t* h, uint32_t* chunk) {
+static inline void sha256Block(uint32_t* h, const uint32_t* chunk) VL_ATTR_ALWINLINE;
+static inline void sha256Block(uint32_t* h, const uint32_t* chunk) {
     uint32_t ah[8];
     const uint32_t* p = chunk;
 
@@ -416,7 +416,7 @@ VSpellCheck::EditDistance VSpellCheck::cutoffDistance(size_t goal_len, size_t ca
     size_t max_length = std::max(goal_len, candidate_len);
     size_t min_length = std::min(goal_len, candidate_len);
     if (max_length <= 1) return 0;
-    if (max_length - min_length <= 1) return std::max(max_length / 3, (size_t)1);
+    if (max_length - min_length <= 1) return std::max(max_length / 3, static_cast<size_t>(1));
     return (max_length + 2) / 3;
 }
 
diff --git a/src/V3TSP.h b/src/V3TSP.h
index b5dc1e2a3..78f93fb09 100644
--- a/src/V3TSP.h
+++ b/src/V3TSP.h
@@ -48,7 +48,6 @@ namespace V3TSP {
     void tspSort(const StateVec& states, StateVec* resultp);
 
     void selfTest();
-}
-
+}  // namespace V3TSP
 
 #endif  // Guard
diff --git a/src/V3Unroll.cpp b/src/V3Unroll.cpp
index 107f62ba6..d09c42540 100644
--- a/src/V3Unroll.cpp
+++ b/src/V3Unroll.cpp
@@ -240,7 +240,7 @@ private:
         if (!simulateTree(initp->rhsp(), NULL, initp, loopValue)) {
             return false;
         }
-        while (1) {
+        while (true) {
             V3Number res = V3Number(initp);
             if (!simulateTree(condp, &loopValue, NULL, res)) {
                 return false;
@@ -300,7 +300,7 @@ private:
         ++m_statLoops;
         if (stmtsp) {
             int times = 0;
-            while (1) {
+            while (true) {
                 UINFO(8,"      Looping "<<loopValue<<endl);
                 V3Number res = V3Number(nodep);
                 if (!simulateTree(condp, &loopValue, NULL, res)) {
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index 5b8e29cf4..4173a79eb 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -2498,7 +2498,7 @@ private:
                                           << VN_CAST(patp->keyp(), Text)->text());
                         }
                     }
-                } while(0);
+                } while (false);
                 // Next
                 if (memp) memp = VN_CAST(memp->nextp(), MemberDType);
                 if (patp) patp = VN_CAST(patp->nextp(), PatMember);
@@ -3392,7 +3392,7 @@ private:
                 // AstPattern requires assignments to pass datatype on PRELIM
                 VL_DO_DANGLING(userIterate(pinp, WidthVP(portp->dtypep(), PRELIM).p()), pinp);
             }
-        } while (0);
+        } while (false);
         // Stage 2
         {
             V3TaskConnects tconnects = V3Task::taskConnects(nodep, nodep->taskp()->stmtsp());
diff --git a/src/VlcMain.cpp b/src/VlcMain.cpp
index 601bea6cd..e24bfa6e9 100644
--- a/src/VlcMain.cpp
+++ b/src/VlcMain.cpp
@@ -111,12 +111,9 @@ void VlcOptions::parseOptsList(int argc, char** argv) {
             }
             shift;
         }  // - options
-        else if (1) {
+        else {
             addReadFile(argv[i]);
             shift;
-        } else {
-            v3fatal("Invalid argument: " << argv[i]);
-            shift;
         }
     }
 #undef shift
@@ -139,7 +136,7 @@ void VlcOptions::showVersion(bool verbose) {
 
 //######################################################################
 
-int main(int argc, char** argv, char** env) {
+int main(int argc, char** argv, char** /*env*/) {
     // General initialization
     std::ios::sync_with_stdio();
 
diff --git a/src/VlcTop.cpp b/src/VlcTop.cpp
index e14e481dd..0e08d299f 100644
--- a/src/VlcTop.cpp
+++ b/src/VlcTop.cpp
@@ -113,7 +113,7 @@ void VlcTop::rank() {
     // O(n^2) Ouch.  Probably the thing to do is randomize the order of data
     // then hierarchically solve a small subset of tests, and take resulting
     // solution and move up to larger subset of tests.  (Aka quick sort.)
-    while (1) {
+    while (true) {
         if (debug()) { UINFO(9, "Left on iter" << nextrank << ": "); remaining.dump(); }
         VlcTest* bestTestp = NULL;
         vluint64_t bestRemain = 0;