[HEXAGON] Auto-vectorization (fp16) for v68 (#12397)

* Auto-vectorization (fp16) for v68

* use tvm.testing.main in fp16 test of tanh_slice op

Author: avquicinc

python/tvm/target/target.py

@@ -724,6 +724,12 @@ def create_llvm_options(cpu_ver, config):  # pylint: disable=unused-argument
 
         llvm_options = config["llvm_options"]
 
+        # To enable auto-vectorization for v68 target added the below llvm-option by default
+        if arch_version == 68:
+            if not llvm_options:
+                llvm_options = ""
+            llvm_options += " -force-hvx-float"
+
         # TVM's option parser doesn't allow '=' in values, but '=' can
         # appear in LLVM flags. Replace it with '@', since it's unlikely
         # that '@' will be used in another context.

tests/python/contrib/test_hexagon/topi/test_tanh_slice.py

@@ -106,4 +106,4 @@ def test_tanh(
 
 
 if __name__ == "__main__":
-    sys.exit(pytest.main(sys.argv))
+    tvm.testing.main()