| Message ID | 20220627190540.13358-4-luc.vanoostenryck@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | allow -1 and compares in bitwise types | expand |
On Mon, Jun 27, 2022 at 12:05 PM Luc Van Oostenryck <luc.vanoostenryck@gmail.com> wrote: > > Currently, bitwise types are restricted to bitwise operations > (&, |, ^ and ~) as well as equality comparisons. > > This patch makes the others comparisons valid for bitwise types > too. > > Warning: This change make sense in the context of [1] but > doesn't make sense for the 'main' bitwise types: > __be32 and friends. Yeah, this is wrong. It will literally break one of the use-cases, which is endianness comparisons. You cannot compare values in the wrong endianness for greater-than or less-than, because you will get the wrong answer - the ordering is different in different byte-orders. But comparing for equality (and inequality) is fine, and we actually do that in the kernel (ie you can take a big-endian value, and compare it with another big-endian value for being equal, without converting it to the local CPU endianness). Now, comparing the *constants* 0 and all-ones is fine. They are smaller than (and larger than) all other values, regardless of any byte/bit order issues. So I think that really needs to check that one (or both) sides are the magic constants. Linus
On 27/06/2022 20:05, Luc Van Oostenryck wrote: > Currently, bitwise types are restricted to bitwise operations > (&, |, ^ and ~) as well as equality comparisons. > > This patch makes the others comparisons valid for bitwise types > too. > > Warning: This change make sense in the context of [1] but The [1] reference seems to be missing :) ATB, Ramsay Jones > doesn't make sense for the 'main' bitwise types: > __be32 and friends. > Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> > --- > evaluate.c | 4 ++++ > validation/bitwise-cmp.c | 1 - > validation/linear/bitwise-cmps.c | 1 - > 3 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/evaluate.c b/evaluate.c > index bcbcdf1ef0cc..bb8c0caa905a 100644 > --- a/evaluate.c > +++ b/evaluate.c > @@ -435,6 +435,10 @@ static int restricted_binop(int op, struct symbol *type) > case '^': > case '?': > return 2; /* keep fouled */ > + case '<': > + case '>': > + case SPECIAL_LTE: > + case SPECIAL_GTE: > case SPECIAL_EQUAL: > case SPECIAL_NOTEQUAL: > return 3; /* warn if fouled */ > diff --git a/validation/bitwise-cmp.c b/validation/bitwise-cmp.c > index ca12b5e51e8e..8c3e6894072d 100644 > --- a/validation/bitwise-cmp.c > +++ b/validation/bitwise-cmp.c > @@ -28,5 +28,4 @@ static int gtx(b32 x, b32 y) { return (x > y); } > > /* > * check-name: bitwise-cmp > - * check-known-to-fail > */ > diff --git a/validation/linear/bitwise-cmps.c b/validation/linear/bitwise-cmps.c > index 6122944a42c6..f83ab7fe47db 100644 > --- a/validation/linear/bitwise-cmps.c > +++ b/validation/linear/bitwise-cmps.c > @@ -8,7 +8,6 @@ static int gtu(bs32 x, bs32 y) { return (x > y); } > /* > * check-name: bitwise-cmps > * check-command: test-linearize -Wno-decl $file > - * check-known-to-fail > * > * check-output-ignore > * check-output-excludes: setb\\.
diff --git a/evaluate.c b/evaluate.c index bcbcdf1ef0cc..bb8c0caa905a 100644 --- a/evaluate.c +++ b/evaluate.c @@ -435,6 +435,10 @@ static int restricted_binop(int op, struct symbol *type) case '^': case '?': return 2; /* keep fouled */ + case '<': + case '>': + case SPECIAL_LTE: + case SPECIAL_GTE: case SPECIAL_EQUAL: case SPECIAL_NOTEQUAL: return 3; /* warn if fouled */ diff --git a/validation/bitwise-cmp.c b/validation/bitwise-cmp.c index ca12b5e51e8e..8c3e6894072d 100644 --- a/validation/bitwise-cmp.c +++ b/validation/bitwise-cmp.c @@ -28,5 +28,4 @@ static int gtx(b32 x, b32 y) { return (x > y); } /* * check-name: bitwise-cmp - * check-known-to-fail */ diff --git a/validation/linear/bitwise-cmps.c b/validation/linear/bitwise-cmps.c index 6122944a42c6..f83ab7fe47db 100644 --- a/validation/linear/bitwise-cmps.c +++ b/validation/linear/bitwise-cmps.c @@ -8,7 +8,6 @@ static int gtu(bs32 x, bs32 y) { return (x > y); } /* * check-name: bitwise-cmps * check-command: test-linearize -Wno-decl $file - * check-known-to-fail * * check-output-ignore * check-output-excludes: setb\\.
Currently, bitwise types are restricted to bitwise operations (&, |, ^ and ~) as well as equality comparisons. This patch makes the others comparisons valid for bitwise types too. Warning: This change make sense in the context of [1] but doesn't make sense for the 'main' bitwise types: __be32 and friends. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> --- evaluate.c | 4 ++++ validation/bitwise-cmp.c | 1 - validation/linear/bitwise-cmps.c | 1 - 3 files changed, 4 insertions(+), 2 deletions(-)