diff mbox series

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

Message ID fa706b192b2a3a0ffbd399fa8dbf0d5b2c5b82d9.1664568492.git.quic_mathbern@quicinc.com (mailing list archive)
State New, archived
Headers show
Series Hexagon (gen_tcg_funcs.py): avoid duplicated tcg code on A_CVI_NEW | expand

Commit Message

Matheus Tavares Bernardino Sept. 30, 2022, 8:08 p.m. UTC
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>
---
 target/hexagon/gen_tcg_funcs.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Richard Henderson Sept. 30, 2022, 8:16 p.m. UTC | #1
On 9/30/22 13:08, Matheus Tavares Bernardino wrote:
> 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>
> ---
>   target/hexagon/gen_tcg_funcs.py | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/hexagon/gen_tcg_funcs.py b/target/hexagon/gen_tcg_funcs.py
> index d72c689ad7..6dea02b0b9 100755
> --- a/target/hexagon/gen_tcg_funcs.py
> +++ b/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")

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~
Taylor Simpson Sept. 30, 2022, 9:52 p.m. UTC | #2
> -----Original Message-----
> From: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
> Sent: Friday, September 30, 2022 3:08 PM
> To: qemu-devel@nongnu.org
> Cc: Taylor Simpson <tsimpson@quicinc.com>
> Subject: [PATCH] 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>
> ---
>  target/hexagon/gen_tcg_funcs.py | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/hexagon/gen_tcg_funcs.py
> b/target/hexagon/gen_tcg_funcs.py index d72c689ad7..6dea02b0b9 100755
> --- a/target/hexagon/gen_tcg_funcs.py
> +++ b/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")

Reviewed-by: Taylor Simpson <tsimpson@quicinc.com>
Philippe Mathieu-Daudé Oct. 3, 2022, 2:25 p.m. UTC | #3
On 30/9/22 22:08, Matheus Tavares Bernardino wrote:
> 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>
> ---
>   target/hexagon/gen_tcg_funcs.py | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
diff mbox series

Patch

diff --git a/target/hexagon/gen_tcg_funcs.py b/target/hexagon/gen_tcg_funcs.py
index d72c689ad7..6dea02b0b9 100755
--- a/target/hexagon/gen_tcg_funcs.py
+++ b/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")