Re: [PATCH v2] lib/zlib_inflate/inffast: Check config in C to avoid unused function warning

[Paul Menzel]

Dear Christophe,


Thank you for the review.

Am 20.09.21 um 10:36 schrieb Christophe Leroy:



Le 20/09/2021 à 09:46, Paul Menzel a écrit :

Building Linux for ppc64le with Ubuntu clang version 12.0.0-3ubuntu1~21.04.1
shows the warning below.

 arch/powerpc/boot/inffast.c:20:1: warning: unused function 
'get_unaligned16' [-Wunused-function]
 get_unaligned16(const unsigned short *p)
 ^
 1 warning generated.

Fix it, by moving the check from the preprocessor to C, so the compiler
sees the use.

Signed-off-by: Paul Menzel 
---
  lib/zlib_inflate/inffast.c | 7 ++-
  1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/lib/zlib_inflate/inffast.c b/lib/zlib_inflate/inffast.c
index f19c4fbe1be7..fb87a3120f0f 100644
--- a/lib/zlib_inflate/inffast.c
+++ b/lib/zlib_inflate/inffast.c
@@ -254,11 +254,8 @@ void inflate_fast(z_streamp strm, unsigned start)
  sfrom = (unsigned short *)(from);
  loops = len >> 1;
  do
-#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
-    *sout++ = *sfrom++;
-#else
-    *sout++ = get_unaligned16(sfrom++);
-#endif
+    *sout++ = 
IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ?

+    *sfrom++ : get_unaligned16(sfrom++);


I think it would be more readable as

do {
     if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
     *sout++ = *sfrom++;
     else
     *sout++ = get_unaligned16(sfrom++);
} while (--loops);


I prefer the ternary operator, as it’s less lines, and it’s clear, that 
only the variable assignment is affected by the condition. But as style 
is subjective, I sent v3.



  while (--loops);
  out = (unsigned char *)sout;
  from = (unsigned char *)sfrom;



Kind regards,

Paul

Re: [PATCH v2] lib/zlib_inflate/inffast: Check config in C to avoid unused function warning

[Christophe Leroy]

Le 20/09/2021 à 09:46, Paul Menzel a écrit :

Building Linux for ppc64le with Ubuntu clang version 12.0.0-3ubuntu1~21.04.1
shows the warning below.

 arch/powerpc/boot/inffast.c:20:1: warning: unused function 
'get_unaligned16' [-Wunused-function]
 get_unaligned16(const unsigned short *p)
 ^
 1 warning generated.

Fix it, by moving the check from the preprocessor to C, so the compiler
sees the use.

Signed-off-by: Paul Menzel 
---
  lib/zlib_inflate/inffast.c | 7 ++-
  1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/lib/zlib_inflate/inffast.c b/lib/zlib_inflate/inffast.c
index f19c4fbe1be7..fb87a3120f0f 100644
--- a/lib/zlib_inflate/inffast.c
+++ b/lib/zlib_inflate/inffast.c
@@ -254,11 +254,8 @@ void inflate_fast(z_streamp strm, unsigned start)
sfrom = (unsigned short *)(from);
loops = len >> 1;
do
-#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
-   *sout++ = *sfrom++;
-#else
-   *sout++ = get_unaligned16(sfrom++);
-#endif
+   *sout++ = 
IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ?
+   *sfrom++ : get_unaligned16(sfrom++);


I think it would be more readable as

do {
if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
*sout++ = *sfrom++;
else
*sout++ = get_unaligned16(sfrom++);
} while (--loops);




while (--loops);
out = (unsigned char *)sout;
from = (unsigned char *)sfrom;

[PATCH v2] lib/zlib_inflate/inffast: Check config in C to avoid unused function warning

[Paul Menzel]

Building Linux for ppc64le with Ubuntu clang version 12.0.0-3ubuntu1~21.04.1
shows the warning below.

arch/powerpc/boot/inffast.c:20:1: warning: unused function 
'get_unaligned16' [-Wunused-function]
get_unaligned16(const unsigned short *p)
^
1 warning generated.

Fix it, by moving the check from the preprocessor to C, so the compiler
sees the use.

Signed-off-by: Paul Menzel 
---
 lib/zlib_inflate/inffast.c | 7 ++-
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/lib/zlib_inflate/inffast.c b/lib/zlib_inflate/inffast.c
index f19c4fbe1be7..fb87a3120f0f 100644
--- a/lib/zlib_inflate/inffast.c
+++ b/lib/zlib_inflate/inffast.c
@@ -254,11 +254,8 @@ void inflate_fast(z_streamp strm, unsigned start)
sfrom = (unsigned short *)(from);
loops = len >> 1;
do
-#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
-   *sout++ = *sfrom++;
-#else
-   *sout++ = get_unaligned16(sfrom++);
-#endif
+   *sout++ = 
IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ?
+   *sfrom++ : get_unaligned16(sfrom++);
while (--loops);
out = (unsigned char *)sout;
from = (unsigned char *)sfrom;
-- 
2.33.0