| Message ID | 1368737733-6475-1-git-send-email-xi.wang@gmail.com (mailing list archive) |
|---|---|
| State | Mainlined, archived |
| Headers | show |
On Thu, May 16, 2013 at 11:55 PM, Xi Wang <xi.wang@gmail.com> wrote: > The results of cast_to() seem unused. Assign them to expr->left and > expr->right. > > Signed-off-by: Xi Wang <xi.wang@gmail.com> How did you find about this? Is this needed to fix a reproducible issue? > --- > evaluate.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/evaluate.c b/evaluate.c > index 0dfa519..d9c767f 100644 > --- a/evaluate.c > +++ b/evaluate.c > @@ -1024,11 +1024,11 @@ static struct symbol *evaluate_compare(struct expression *expr) > goto OK; > } > if (is_null1 && (rclass & TYPE_PTR)) { > - left = cast_to(left, rtype); > + expr->left = cast_to(left, rtype); > goto OK; > } > if (is_null2 && (lclass & TYPE_PTR)) { > - right = cast_to(right, ltype); > + expr->right = cast_to(right, ltype); > goto OK; > } > } > @@ -1044,11 +1044,11 @@ static struct symbol *evaluate_compare(struct expression *expr) > if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) { > if (ltype->ctype.as == rtype->ctype.as) { > if (lbase == &void_ctype) { > - right = cast_to(right, ltype); > + expr->right = cast_to(right, ltype); > goto OK; > } > if (rbase == &void_ctype) { > - left = cast_to(left, rtype); > + expr->left = cast_to(left, rtype); > goto OK; > } > } > -- > 1.8.1.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-sparse" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, May 19, 2013 at 3:48 AM, Pekka Enberg <penberg@kernel.org> wrote:
> How did you find about this? Is this needed to fix a reproducible issue?
I was debugging like (p == 0) and noticed that sparse lost this cast
to pointers.
A more serious problem in evaluate_compare() is that sparse evaluates
comparisons to bool, which should have been int, according to the C
standard.
For example, sparse incorrectly evaluates sizeof(1 == 0) to 1, while
gcc and clang evaluate this to 4 (i.e., sizeof(int)).
Similar problems exist when sparse evaluates other conditional
expressions, such as !, &&, ||.
This also confuses sparse-llvm. For example, given OP_AND_BOOL x, y,
should sparse-llvm assume that x and y can be int, bool, or some other
type?
- xi
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diff --git a/evaluate.c b/evaluate.c index 0dfa519..d9c767f 100644 --- a/evaluate.c +++ b/evaluate.c @@ -1024,11 +1024,11 @@ static struct symbol *evaluate_compare(struct expression *expr) goto OK; } if (is_null1 && (rclass & TYPE_PTR)) { - left = cast_to(left, rtype); + expr->left = cast_to(left, rtype); goto OK; } if (is_null2 && (lclass & TYPE_PTR)) { - right = cast_to(right, ltype); + expr->right = cast_to(right, ltype); goto OK; } } @@ -1044,11 +1044,11 @@ static struct symbol *evaluate_compare(struct expression *expr) if (expr->op == SPECIAL_EQUAL || expr->op == SPECIAL_NOTEQUAL) { if (ltype->ctype.as == rtype->ctype.as) { if (lbase == &void_ctype) { - right = cast_to(right, ltype); + expr->right = cast_to(right, ltype); goto OK; } if (rbase == &void_ctype) { - left = cast_to(left, rtype); + expr->left = cast_to(left, rtype); goto OK; } }
The results of cast_to() seem unused. Assign them to expr->left and expr->right. Signed-off-by: Xi Wang <xi.wang@gmail.com> --- evaluate.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)