add missing test file

examples/tests/cv_nand/cv_nand.c

@@ -0,0 +1,16 @@
+// RUN: clang -cc1 -triple riscv32 -target-feature +m -target-feature +xcvnand -S -O3 %s -o - \
+// RUN:     | FileCheck %s  -check-prefix=CHECK
+
+// CHECK-LABEL: nand_bitwise_s32:
+// CHECK-COUNT-1: cv.nand_bitwise {{.*}}
+signed int nand_bitwise_s32(signed int a, signed int b)
+{
+  return ~(a & b);
+}
+
+// CHECK-LABEL: nand_bitwise_u32:
+// CHECK-COUNT-1: cv.nand_bitwise {{.*}}
+unsigned int nand_bitwise_u32(unsigned int a, unsigned int b)
+{
+  return ~(a & b);
+}

examples/tests/cv_nand/cv_nand.s

@@ -0,0 +1,9 @@
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+xcvnand -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+xcvnand < %s \
+# RUN:     | llvm-objdump --mattr=+xcvnand -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
+
+# CHECK-ASM-AND-OBJ: cv.nand_bitwise a4, ra, s0
+# CHECK-ASM: encoding: [0x2b,0xe7,0x80,0x92]
+cv.nand_bitwise a4, ra, s0

examples/tests/cv_nand/cv_nand_invalid.s

@@ -0,0 +1,3 @@
+# RUN: not llvm-mc -triple riscv32 -mattr=+m < %s 2>&1 | FileCheck %s
+
+cv.nand_bitwise a4, ra, s0 # CHECK: :[[@LINE]]:1: error: instruction requires the following: 'Xcvnand' (None)