Hexagon (gen_tcg_funcs.py): avoid duplicated tcg code on A_CVI_NEW

Hexagon instructions with the A_CVI_NEW attribute produce a vector value
that can be used in the same packet. The python function responsible for
generating code for such instructions has a typo ("if" instead of
"elif"), which makes genptr_dst_write_ext() be executed twice, thus also
generating the same tcg code twice. Fortunately, this doesn't cause any
problems for correctness, but it is less efficient than it could be. Fix
it by using an "elif" and avoiding the unnecessary extra code gen.

Signed-off-by: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Taylor Simpson <tsimpson@quicinc.com>
Message-Id: <fa706b192b2a3a0ffbd399fa8dbf0d5b2c5b82d9.1664568492.git.quic_mathbern@quicinc.com>

target/hexagon/gen_tcg_funcs.py

@@ -548,7 +548,7 @@ def genptr_dst_write_opn(f,regtype, regid, tag):
         if (hex_common.is_hvx_reg(regtype)):
             if (hex_common.is_new_result(tag)):
                 genptr_dst_write_ext(f, tag, regtype, regid, "EXT_NEW")
-            if (hex_common.is_tmp_result(tag)):
+            elif (hex_common.is_tmp_result(tag)):
                 genptr_dst_write_ext(f, tag, regtype, regid, "EXT_TMP")
             else:
                 genptr_dst_write_ext(f, tag, regtype, regid, "EXT_DFL")