diff --git a/.travis.yml b/.travis.yml
index 1de130691..319443126 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -49,6 +49,13 @@ before_script:
       export SYSTEMC_INCLUDE=/usr/include
       export SYSTEMC_LIBDIR=/usr/lib/x86_64-linux-gnu
     fi
+  # Override compiler for M32
+  - |
+    if [ "$M32" = "1" ]; then
+      export CC="$CC -m32"
+      export CXX="$CXX -m32"
+      unset M32 # verilated.mk actually references $(M32) so unset
+    fi
 
 before_cache:
   - ccache -s -z
@@ -72,6 +79,8 @@ jobs:
     - {stage: build,                   os: linux, dist: focal,  compiler: clang, workspaces: {create: {name: focal-clang,  paths: .}}}
     # Coverage build
     - {stage: build, if: type  = cron, os: linux, dist: focal,  compiler: gcc,   workspaces: {create: {name: coverage,     paths: .}}, env: COVERAGE=1}
+    # 32-bit build
+    - {stage: build, if: type  = cron, os: linux, dist: focal,  compiler: gcc,   workspaces: {create: {name: focal-gcc-m32, paths: .}}, env: M32=1}
     # OS X build
     - {stage: build, if: type  = cron, os: osx, osx_image: xcode11.6, compiler: clang, workspaces: {create: {name: osx-xcode11.6, paths: .}}}
     # FreeBSD build
@@ -115,6 +124,11 @@ jobs:
     - {stage: test, if: type  = cron, os: linux, dist: focal,  compiler: gcc,   workspaces: {use: coverage},     git: {clone: false}, env: TESTS=coverage-vltmt-1}
     - {stage: test, if: type  = cron, os: linux, dist: focal,  compiler: gcc,   workspaces: {use: coverage},     git: {clone: false}, env: TESTS=coverage-vltmt-2}
     - {stage: test, if: type  = cron, os: linux, dist: focal,  compiler: gcc,   workspaces: {use: coverage},     git: {clone: false}, env: TESTS=coverage-vltmt-3}
+    # 32-bit tests
+    - {stage: test, if: type  = cron, os: linux, dist: focal,  compiler: gcc,   workspaces: {use: focal-gcc-m32}, git: {clone: false}, env: [M32=1, TESTS=dist-vlt-0]}
+    - {stage: test, if: type  = cron, os: linux, dist: focal,  compiler: gcc,   workspaces: {use: focal-gcc-m32}, git: {clone: false}, env: [M32=1, TESTS=dist-vlt-1]}
+    - {stage: test, if: type  = cron, os: linux, dist: focal,  compiler: gcc,   workspaces: {use: focal-gcc-m32}, git: {clone: false}, env: [M32=1, TESTS=vltmt-0]}
+    - {stage: test, if: type  = cron, os: linux, dist: focal,  compiler: gcc,   workspaces: {use: focal-gcc-m32}, git: {clone: false}, env: [M32=1, TESTS=vltmt-1]}
     # OS X tests
     - {stage: test, if: type  = cron, os: osx, osx_image: xcode11.6, compiler: clang, workspaces: {use: osx-xcode11.6},  git: {clone: false}, env: TESTS=dist-vlt-0}
     - {stage: test, if: type  = cron, os: osx, osx_image: xcode11.6, compiler: clang, workspaces: {use: osx-xcode11.6},  git: {clone: false}, env: TESTS=dist-vlt-1}
diff --git a/ci/travis-install.bash b/ci/travis-install.bash
index e75e765f4..f4c89c9bd 100755
--- a/ci/travis-install.bash
+++ b/ci/travis-install.bash
@@ -55,6 +55,9 @@ if [ "$TRAVIS_BUILD_STAGE_NAME" = "build" ]; then
     if [ "$COVERAGE" = 1 ]; then
       yes yes | sudo cpan -fi Unix::Processors Parallel::Forker
     fi
+    if [ "$M32" = 1 ]; then
+      sudo apt-get install gcc-multilib g++-multilib
+    fi
   elif [ "$TRAVIS_OS_NAME" = "osx" ]; then
     brew update
     brew install ccache perl gperftools
@@ -74,6 +77,9 @@ elif [ "$TRAVIS_BUILD_STAGE_NAME" = "test" ]; then
     if [ "$TRAVIS_DIST" = "focal" ]; then
       sudo apt-get install libsystemc-dev
     fi
+    if [ "$M32" = 1 ]; then
+      sudo apt-get install lib32z1-dev gcc-multilib g++-multilib
+    fi
     yes yes | sudo cpan -fi Unix::Processors Parallel::Forker
     # Not listing Bit::Vector as slow to install, and only skips one test
     install-vcddiff
diff --git a/configure.ac b/configure.ac
index 53ff82eaa..a09125d96 100644
--- a/configure.ac
+++ b/configure.ac
@@ -447,14 +447,18 @@ AC_CHECK_MEMBER([struct stat.st_mtim.tv_nsec],
 # - If not found or not system-wide, user can set SYSTEMC_INCLUDE.
 # AC_CHECK_HEADERS seems to not locate on Travis-CI but include does work.
 AC_MSG_CHECKING([whether SystemC is found (in system path)])
-AC_COMPILE_IFELSE(
+ACO_SAVE_LIBS="$LIBS"
+LIBS="$LIBS -lsystemc"
+AC_LINK_IFELSE(
     [AC_LANG_PROGRAM([[#include <systemc.h>
-                     ]],[])],
+                     extern "C" int sc_main(int argc, char* argv[]) {}
+                     ]],[[sc_version()]])],
     [_my_result=yes
-     AC_DEFINE([HAVE_SYSTEMC_H],[1],[Defined if have systemc.h])],
+     AC_DEFINE([HAVE_SYSTEMC],[1],[Defined if have SystemC library])],
     [_my_result=no])
 AC_MSG_RESULT($_my_result)
-AC_SUBST(HAVE_SYSTEMC_H)
+LIBS="$ACO_SAVE_LIBS"
+AC_SUBST(HAVE_SYSTEMC)
 
 # Checks for system services
 
diff --git a/include/verilated.h b/include/verilated.h
index e375146c0..60fd02949 100644
--- a/include/verilated.h
+++ b/include/verilated.h
@@ -843,7 +843,7 @@ inline vluint64_t vl_time_stamp64() { return static_cast<vluint64_t>(sc_time_sta
 // Optimized assuming scale is always constant.
 // Can't use multiply in Q flavor, as might lose precision
 #define VL_TIME_UNITED_Q(scale) (VL_TIME_Q() / static_cast<QData>(scale))
-#define VL_TIME_UNITED_D(scale) (VL_TIME_D() * (1.0 / (scale)))
+#define VL_TIME_UNITED_D(scale) (VL_TIME_D() / static_cast<double>(scale))
 /// Time imported from units to time precision
 double vl_time_multiplier(int scale);
 
diff --git a/src/V3Options.cpp b/src/V3Options.cpp
index 1fe8c3a1e..0dd0d337d 100644
--- a/src/V3Options.cpp
+++ b/src/V3Options.cpp
@@ -568,7 +568,7 @@ string V3Options::getenvVERILATOR_ROOT() {
 }
 
 bool V3Options::systemCSystemWide() {
-#ifdef HAVE_SYSTEMC_H
+#ifdef HAVE_SYSTEMC
     return true;
 #else
     return false;
diff --git a/src/config_build.h.in b/src/config_build.h.in
index 250ac1f96..f31046e03 100644
--- a/src/config_build.h.in
+++ b/src/config_build.h.in
@@ -80,7 +80,7 @@ using std::make_pair;
 // Define if SystemC found
 // - If defined, the default search path has it, so support is always enabled.
 // - If undef, not system-wide, user can set SYSTEMC_INCLUDE.
-#undef HAVE_SYSTEMC_H
+#undef HAVE_SYSTEMC
 
 //**********************************************************************
 //**** OS and compiler specifics
diff --git a/test_regress/driver.pl b/test_regress/driver.pl
index 8ab33a51b..0c5dc3851 100755
--- a/test_regress/driver.pl
+++ b/test_regress/driver.pl
@@ -9,7 +9,8 @@ BEGIN {
     if (!$ENV{VERILATOR_ROOT} && -x "../bin/verilator") {
         $ENV{VERILATOR_ROOT} = Cwd::getcwd()."/..";
     }
-    $ENV{MAKE} ||= "make"
+    $ENV{MAKE} ||= "make";
+    $ENV{CXX} ||= "c++";
 }
 
 use Getopt::Long;
@@ -1165,7 +1166,7 @@ sub compile {
 
     if ($param{make_pli}) {
         $self->oprint("Compile vpi\n") if $self->{verbose};
-        my @cmd = ('c++', @{$param{pli_flags}}, "-DIS_VPI",
+        my @cmd = ($ENV{CXX}, @{$param{pli_flags}}, "-DIS_VPI",
                    "$self->{t_dir}/$self->{pli_filename}");
 
         $self->_run(logfile=>"$self->{obj_dir}/pli_compile.log",
diff --git a/test_regress/t/t_flag_ldflags.pl b/test_regress/t/t_flag_ldflags.pl
index e1feb205b..db80da480 100755
--- a/test_regress/t/t_flag_ldflags.pl
+++ b/test_regress/t/t_flag_ldflags.pl
@@ -11,13 +11,13 @@ if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); di
 scenarios(vlt => 1);
 
 run(cmd => ["cd $Self->{obj_dir}"
-            ." && c++ -c ../../t/t_flag_ldflags_a.cpp"
+            ." && $ENV{CXX} -c ../../t/t_flag_ldflags_a.cpp"
             ." && ar -cr t_flag_ldflags_a.a t_flag_ldflags_a.o"
             ." && ranlib t_flag_ldflags_a.a "],
     check_finished => 0);
 run(cmd => ["cd $Self->{obj_dir}"
-            ." && c++ -fPIC -c ../../t/t_flag_ldflags_so.cpp"
-            ." && c++ -shared -o t_flag_ldflags_so.so -lc t_flag_ldflags_so.o"],
+            ." && $ENV{CXX} -fPIC -c ../../t/t_flag_ldflags_so.cpp"
+            ." && $ENV{CXX} -shared -o t_flag_ldflags_so.so -lc t_flag_ldflags_so.o"],
     check_finished => 0);
 
 compile(