diff --git a/appveyor.yml b/appveyor.yml
index 4e175514b..4ca454ca9 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -55,7 +55,7 @@ for:
           echo ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"
           echo ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> NO WARNINGS"
           echo ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"
-          src\engine\b2.exe --debug-configuration b2 warnings-as-errors=on toolset=%TEST_TOOLSET%
+          src\engine\b2.exe --debug-configuration b2 warnings-as-errors=on variant=debug,release address-model=32,64 toolset=%TEST_TOOLSET%
       - cmd: |
           echo ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"
           echo ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> BOOTSTRAP"
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index a520147ef..0452dda6f 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -164,14 +164,8 @@ stages:
           set -e
           CXX_PATH=`which ${CXX}`
           echo "using ${TEST_TOOLSET} : : ${CXX_PATH} ;" > ${HOME}/user-config.jam
-          ./src/engine/b2 b2 warnings-as-errors=on toolset=${TEST_TOOLSET}
+          ./src/engine/b2 b2 warnings-as-errors=on variant=debug,release address-model=32,64 toolset=${TEST_TOOLSET}
       displayName: "No Warnings"
-    - bash: |
-          set -e
-          CXX_PATH=`which ${CXX}`
-          echo "using ${TEST_TOOLSET} : : ${CXX_PATH} ;" > ${HOME}/user-config.jam
-          ./src/engine/b2 b2 warnings-as-errors=on toolset=${TEST_TOOLSET} address-model=64
-      displayName: "No-Warn 64bit"
     - bash: |
           set -e
           CXX_PATH=`which ${CXX}`
@@ -216,14 +210,8 @@ stages:
           $env:HOME = $env:HOMEDRIVE + $env:HOMEPATH
           $env:path += ';' + $env:CXX_PATH
           echo "using" $env:TEST_TOOLSET ":" ":" $env:CXX ";" > $env:HOME/user-config.jam
-          ./src/engine/b2.exe --debug-configuration b2 warnings-as-errors=on toolset=$env:TEST_TOOLSET
+          ./src/engine/b2.exe --debug-configuration b2 warnings-as-errors=on variant=debug,release toolset=$env:TEST_TOOLSET
       displayName: "No Warnings"
-    - powershell: |
-          $env:HOME = $env:HOMEDRIVE + $env:HOMEPATH
-          $env:path += ';' + $env:CXX_PATH
-          echo "using" $env:TEST_TOOLSET ":" ":" $env:CXX ";" > $env:HOME/user-config.jam
-          ./src/engine/b2.exe --debug-configuration b2 warnings-as-errors=on toolset=$env:TEST_TOOLSET address-model=64
-      displayName: "No-Warn 64bit"
     - powershell: |
           $env:HOME = $env:HOMEDRIVE + $env:HOMEPATH
           $env:path += ';' + $env:CXX_PATH
@@ -323,14 +311,8 @@ stages:
         set -e
         CXX_PATH=`which ${CXX}`
         echo "using ${TEST_TOOLSET} : : ${CXX_PATH} ;" > ${HOME}/user-config.jam
-        ./src/engine/b2 b2 warnings-as-errors=on toolset=${TEST_TOOLSET}
+        ./src/engine/b2 b2 warnings-as-errors=on variant=debug,release address-model,32,64 toolset=${TEST_TOOLSET}
       displayName: "No Warnings"
-    - bash: |
-          set -e
-          CXX_PATH=`which ${CXX}`
-          echo "using ${TEST_TOOLSET} : : ${CXX_PATH} ;" > ${HOME}/user-config.jam
-          ./src/engine/b2 b2 warnings-as-errors=on toolset=${TEST_TOOLSET} address-model=64
-      displayName: "No-Warn 64bit"
     - bash: |
         set -e
         CXX_PATH=`which ${CXX}`
diff --git a/src/engine/debugger.cpp b/src/engine/debugger.cpp
index 3486c60c0..97eeb6f06 100644
--- a/src/engine/debugger.cpp
+++ b/src/engine/debugger.cpp
@@ -160,11 +160,10 @@ static LIST * debug_list_read( FILE * in )
 {
     int len;
     int i;
-    int ch;
     LIST * result = L0;
     fscanf( in, "%d", &len );
-    ch = fgetc( in );
-    assert( ch == '\n' );
+    int ch = fgetc( in );
+    if (ch > 0) assert( ch == '\n' );
     for ( i = 0; i < len; ++i )
     {
         result = list_push_back( result, debug_object_read( in ) );
diff --git a/src/engine/execcmd.cpp b/src/engine/execcmd.cpp
index b6c715171..dfbd5a7f8 100644
--- a/src/engine/execcmd.cpp
+++ b/src/engine/execcmd.cpp
@@ -41,9 +41,9 @@ static int intr;
  */
 
 void argv_from_shell( char const * * argv, LIST * shell, char const * command,
-    int const slot )
+    int32_t const slot )
 {
-    static char jobno[ 4 ];
+    static char jobno[ 12 ];
 
     int i;
     int gotpercent = 0;
diff --git a/src/engine/execcmd.h b/src/engine/execcmd.h
index 206fb7788..fa24e432d 100644
--- a/src/engine/execcmd.h
+++ b/src/engine/execcmd.h
@@ -91,7 +91,7 @@ void exec_wait();
  * given shell list.
  */
 void argv_from_shell( char const * * argv, LIST * shell, char const * command,
-    int const slot );
+    int32_t const slot );
 
 /* Interrupt routine bumping the internal interrupt counter. Needs to be
  * registered by platform specific exec*.c modules.
diff --git a/src/engine/function.cpp b/src/engine/function.cpp
index d8971471c..357f331c3 100644
--- a/src/engine/function.cpp
+++ b/src/engine/function.cpp
@@ -3193,7 +3193,7 @@ void argument_list_push( struct arg_list * formal, int32_t formal_count,
         for ( j = 0; j < formal[ i ].size; ++j )
         {
             struct argument * formal_arg = &formal[ i ].args[ j ];
-            LIST * value;
+            LIST * value = L0;
 
             switch ( formal_arg->flags )
             {
@@ -3871,7 +3871,9 @@ LIST * function_run( FUNCTION * function_, FRAME * frame, STACK * s )
     LIST * l;
     LIST * r;
     LIST * result = L0;
+#ifndef NDEBUG
     void * saved_stack = s->data;
+#endif
 
     PROFILE_ENTER_LOCAL(function_run);
 
@@ -4250,8 +4252,8 @@ LIST * function_run( FUNCTION * function_, FRAME * frame, STACK * s )
                 backtrace( frame );
                 assert( saved_stack == s->data );
             }
-#endif
             assert( saved_stack == s->data );
+#endif
             debug_on_exit_function( function->base.rulename );
             PROFILE_EXIT_LOCAL(function_run_INSTR_RETURN);
             PROFILE_EXIT_LOCAL(function_run);
diff --git a/src/engine/jam_strings.cpp b/src/engine/jam_strings.cpp
index b8511dd89..bee8e0bbf 100644
--- a/src/engine/jam_strings.cpp
+++ b/src/engine/jam_strings.cpp
@@ -26,7 +26,7 @@ static void assert_invariants( string * self )
     }
 
     assert( self->size < self->capacity );
-    assert( ( self->capacity <= sizeof( self->opt ) ) == ( self->value == self->opt ) );
+    assert( ( self->capacity <= int32_t(sizeof( self->opt )) ) == ( self->value == self->opt ) );
     assert( self->value[ self->size ] == 0 );
     /* String objects modified manually after construction to contain embedded
      * '\0' characters are considered structurally valid.
@@ -198,7 +198,7 @@ void string_unit_test()
         for ( i = 0; i < limit; ++i )
         {
             string_push_back( s, (char)( i + 1 ) );
-            assert( s->size == i + 1 );
+            assert( s->size == int32_t(i + 1) );
         }
         assert( s->size == limit );
         assert( s->value != s->opt );
diff --git a/src/engine/lists.cpp b/src/engine/lists.cpp
index 36b1ca950..d646c6e22 100644
--- a/src/engine/lists.cpp
+++ b/src/engine/lists.cpp
@@ -365,7 +365,7 @@ LIST * list_unique( LIST * sorted_list )
 
 void list_done()
 {
-    for ( int32_t i = 0; i < sizeof( freelist ) / sizeof( freelist[ 0 ] ); ++i )
+    for ( int32_t i = 0; i < int32_t(sizeof( freelist ) / sizeof( freelist[ 0 ] )); ++i )
     {
         LIST * l = freelist[ i ];
         while ( l )
diff --git a/src/engine/make1.cpp b/src/engine/make1.cpp
index 1e200d9ed..0e6e49e6d 100644
--- a/src/engine/make1.cpp
+++ b/src/engine/make1.cpp
@@ -1065,11 +1065,11 @@ static void swap_settings
 static CMD * make1cmds( TARGET * t )
 {
     CMD * cmds = 0;
-    CMD * last_cmd;
+    CMD * last_cmd = 0;
     LIST * shell = L0;
     module_t * settings_module = 0;
     TARGET * settings_target = 0;
-    ACTIONS * a0;
+    ACTIONS * a0 = 0;
     int32_t const running_flag = globs.noexec ? A_RUNNING_NOEXEC : A_RUNNING;
 
     /* Step through actions.
diff --git a/src/engine/object.cpp b/src/engine/object.cpp
index 332b45751..069bc215e 100644
--- a/src/engine/object.cpp
+++ b/src/engine/object.cpp
@@ -229,20 +229,6 @@ static char const * string_set_insert( string_set * set, char const * string,
 }
 
 
-static struct hash_item * object_get_item( OBJECT * obj )
-{
-    return (struct hash_item *)( (char *)obj - offsetof( struct hash_item, data
-        ) );
-}
-
-
-static void object_validate( OBJECT * obj )
-{
-    assert( obj );
-    assert( object_get_item( obj )->header.magic == OBJECT_MAGIC );
-}
-
-
 /*
  * object_new_range() - create an object from a string of given length
  */
@@ -283,6 +269,20 @@ OBJECT * object_new( char const * const string )
 
 #ifndef object_copy
 
+static struct hash_item * object_get_item( OBJECT * obj )
+{
+    return (struct hash_item *)( (char *)obj - offsetof( struct hash_item, data
+        ) );
+}
+
+
+static void object_validate( OBJECT * obj )
+{
+    assert( obj );
+    assert( object_get_item( obj )->header.magic == OBJECT_MAGIC );
+}
+
+
 /*
  * object_copy() - return a copy of an object
  */