diff --git a/Makefile b/Makefile
index fa95b7b70..4d15ed721 100644
--- a/Makefile
+++ b/Makefile
@@ -215,7 +215,7 @@ ABC_ARCHFLAGS += "-DABC_NO_RLIMIT"
 endif
 
 ifeq ($(CONFIG),clang)
-CXX = clang
+CXX = clang++
 LD = clang++
 CXXFLAGS += -std=$(CXXSTD) -Os
 ABCMKARGS += ARCHFLAGS="-DABC_USE_STDINT_H -Wno-c++11-narrowing $(ABC_ARCHFLAGS)"
diff --git a/tests/fmt/run-test.sh b/tests/fmt/run-test.sh
index 914a72347..bc0b129d2 100644
--- a/tests/fmt/run-test.sh
+++ b/tests/fmt/run-test.sh
@@ -51,7 +51,7 @@ test_cxxrtl () {
 	local subtest=$1; shift
 
 	../../yosys -p "read_verilog ${subtest}.v; proc; clean; write_cxxrtl -print-output std::cerr yosys-${subtest}.cc"
-	${CC:-gcc} -std=c++11 -o yosys-${subtest} -I../.. ${subtest}_tb.cc -lstdc++
+	${CXX:-gcc} -std=c++11 -o yosys-${subtest} -I../.. ${subtest}_tb.cc -lstdc++
 	./yosys-${subtest} 2>yosys-${subtest}.log
 	iverilog -o iverilog-${subtest} ${subtest}.v ${subtest}_tb.v
 	./iverilog-${subtest} |grep -v '\$finish called' >iverilog-${subtest}.log
@@ -69,7 +69,7 @@ diff iverilog-always_full.log iverilog-always_full-1.log
 
 ../../yosys -p "read_verilog display_lm.v" >yosys-display_lm.log
 ../../yosys -p "read_verilog display_lm.v; write_cxxrtl yosys-display_lm.cc"
-${CC:-gcc} -std=c++11 -o yosys-display_lm_cc -I../.. display_lm_tb.cc -lstdc++
+${CXX:-gcc} -std=c++11 -o yosys-display_lm_cc -I../.. display_lm_tb.cc -lstdc++
 ./yosys-display_lm_cc >yosys-display_lm_cc.log
 for log in yosys-display_lm.log yosys-display_lm_cc.log; do
 	grep "^%l: \\\\bot\$" "$log"