Some warnings compiling LAPACKE with gcc

[jgpallero]

I've compiled Lapack 3.11.0 in Debian with gcc 12.2.0. All works well, but some warnings have been appeared compiling LAPACKE. There are not any serious, but I paste them here:

gcc -O3 -Wall -I../include -c -o lapacke_zlarfb.o lapacke_zlarfb.c
lapacke_zlarfb.c: In function ‘LAPACKE_zlarfb’:
lapacke_zlarfb.c:63:22: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   63 |         if( !forward && ( col && k > nrows_v ) || ( !col && k > ncols_v )) {
      |             ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
gcc -O3 -Wall -I../include -c -o lapacke_zlarfb_work.o lapacke_zlarfb_work.c
lapacke_zlarfb_work.c: In function ‘LAPACKE_zlarfb_work’:
lapacke_zlarfb_work.c:84:22: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   84 |         if( !forward && ( col && k > nrows_v ) || ( !col && k > ncols_v )) {
      |             ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

gcc -O3 -Wall -I../include -c -o lapacke_dlarfb.o lapacke_dlarfb.c
lapacke_dlarfb.c: In function ‘LAPACKE_dlarfb’:
lapacke_dlarfb.c:62:22: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   62 |         if( !forward && ( col && k > nrows_v ) || ( !col && k > ncols_v )) {
      |             ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
gcc -O3 -Wall -I../include -c -o lapacke_dlarfb_work.o lapacke_dlarfb_work.c
lapacke_dlarfb_work.c: In function ‘LAPACKE_dlarfb_work’:
lapacke_dlarfb_work.c:83:22: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   83 |         if( !forward && ( col && k > nrows_v ) || ( !col && k > ncols_v )) {
      |             ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

gcc -O3 -Wall -I../include -c -o lapacke_clarfb.o lapacke_clarfb.c
lapacke_clarfb.c: In function ‘LAPACKE_clarfb’:
lapacke_clarfb.c:63:22: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   63 |         if( !forward && ( col && k > nrows_v ) || ( !col && k > ncols_v )) {
      |             ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
gcc -O3 -Wall -I../include -c -o lapacke_clarfb_work.o lapacke_clarfb_work.c
lapacke_clarfb_work.c: In function ‘LAPACKE_clarfb_work’:
lapacke_clarfb_work.c:84:22: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   84 |         if( !forward && ( col && k > nrows_v ) || ( !col && k > ncols_v )) {
      |             ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

gcc -O3 -Wall -I../include -c -o lapacke_slarfb.o lapacke_slarfb.c
lapacke_slarfb.c: In function ‘LAPACKE_slarfb’:
lapacke_slarfb.c:62:22: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   62 |         if( !forward && ( col && k > nrows_v ) || ( !col && k > ncols_v )) {
      |             ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
gcc -O3 -Wall -I../include -c -o lapacke_slarfb_work.o lapacke_slarfb_work.c
lapacke_slarfb_work.c: In function ‘LAPACKE_slarfb_work’:
lapacke_slarfb_work.c:83:22: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   83 |         if( !forward && ( col && k > nrows_v ) || ( !col && k > ncols_v )) {
      |             ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

[langou]

Hi @jgpallero,

thanks for the comment.

&& has a higher order of precedence in C than ||, so

a && b || c

is same as

(a && b ) || c

I agree with gcc though that it would be good to have "parentheses around && within ||". (And it would also have the added benefit to remove the gcc warning.)

This issue was already mentioned in #742 .

@jgpallero : can you propose a PR?

Julien.

[langou]

Sorry for the back and forth @jgpallero. I reviewed the comments posted by @ACSimon33 in #742 (comment)_

And I agree. We should remove the !forward test.

So the line of code

if( !forward && ( col && k > nrows_v ) || ( !col && k > ncols_v ))

should be changed to

if( ( col && k > nrows_v ) || ( !col && k > ncols_v ) )

in eight files.

I am sorry for the misdirection.

@jgpallero: Would you be willing to submit another PR?