* overflow check in extract_range_from_binary_1 useless?
@ 2018-06-08 10:38 Aldy Hernandez
2018-06-13 11:42 ` Richard Biener
0 siblings, 1 reply; 3+ messages in thread
From: Aldy Hernandez @ 2018-06-08 10:38 UTC (permalink / raw)
To: Richard Biener, GCC Mailing List; +Cc: Andrew MacLeod
Howdy.
Am I missing something or are these two sets identical?
> /* Get the lower and upper bounds of the type. */
> if (TYPE_OVERFLOW_WRAPS (expr_type))
> {
> type_min = wi::min_value (prec, sgn);
> type_max = wi::max_value (prec, sgn);
> }
> else
> {
> type_min = wi::to_wide (vrp_val_min (expr_type));
> type_max = wi::to_wide (vrp_val_max (expr_type));
> }
Isn't wi::to_wide(TYPE_MIN/MAX_VALUE) the same as wi::min/max_value, or
is there some weird language (*cough ada*) subtlety I'm missing?
Confused.
Aldy
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: overflow check in extract_range_from_binary_1 useless?
2018-06-08 10:38 overflow check in extract_range_from_binary_1 useless? Aldy Hernandez
@ 2018-06-13 11:42 ` Richard Biener
2018-07-05 22:06 ` Jeff Law
0 siblings, 1 reply; 3+ messages in thread
From: Richard Biener @ 2018-06-13 11:42 UTC (permalink / raw)
To: Aldy Hernandez; +Cc: GCC Development, Andrew MacLeod
On Fri, Jun 8, 2018 at 11:42 AM Aldy Hernandez <aldyh@redhat.com> wrote:
>
> Howdy.
>
> Am I missing something or are these two sets identical?
>
> > /* Get the lower and upper bounds of the type. */
> > if (TYPE_OVERFLOW_WRAPS (expr_type))
> > {
> > type_min = wi::min_value (prec, sgn);
> > type_max = wi::max_value (prec, sgn);
> > }
> > else
> > {
> > type_min = wi::to_wide (vrp_val_min (expr_type));
> > type_max = wi::to_wide (vrp_val_max (expr_type));
> > }
>
> Isn't wi::to_wide(TYPE_MIN/MAX_VALUE) the same as wi::min/max_value, or
> is there some weird language (*cough ada*) subtlety I'm missing?
It might have subtle differences for -fstrict-enums or other language specific
types where the legal value-range doesn't cover all of the types precision.
I think you can safely use the wi::max/min_value variant and IMHO
vrp_val_min/max should use wi::min/max_value as well (well, it returns
a tree so better not re-create that all the time).
Richard.
> Confused.
> Aldy
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: overflow check in extract_range_from_binary_1 useless?
2018-06-13 11:42 ` Richard Biener
@ 2018-07-05 22:06 ` Jeff Law
0 siblings, 0 replies; 3+ messages in thread
From: Jeff Law @ 2018-07-05 22:06 UTC (permalink / raw)
To: Richard Biener, Aldy Hernandez; +Cc: GCC Development, Andrew MacLeod
On 06/13/2018 05:18 AM, Richard Biener wrote:
> On Fri, Jun 8, 2018 at 11:42 AM Aldy Hernandez <aldyh@redhat.com> wrote:
>>
>> Howdy.
>>
>> Am I missing something or are these two sets identical?
>>
>>> /* Get the lower and upper bounds of the type. */
>>> if (TYPE_OVERFLOW_WRAPS (expr_type))
>>> {
>>> type_min = wi::min_value (prec, sgn);
>>> type_max = wi::max_value (prec, sgn);
>>> }
>>> else
>>> {
>>> type_min = wi::to_wide (vrp_val_min (expr_type));
>>> type_max = wi::to_wide (vrp_val_max (expr_type));
>>> }
>>
>> Isn't wi::to_wide(TYPE_MIN/MAX_VALUE) the same as wi::min/max_value, or
>> is there some weird language (*cough ada*) subtlety I'm missing?
>
> It might have subtle differences for -fstrict-enums or other language specific
> types where the legal value-range doesn't cover all of the types precision.
>
> I think you can safely use the wi::max/min_value variant and IMHO
> vrp_val_min/max should use wi::min/max_value as well (well, it returns
> a tree so better not re-create that all the time).
Or even C++ perhaps where an enum object can take on values outside the
enum.
Jeff
^ permalink raw reply [flat|nested] 3+ messages in thread
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2018-06-08 10:38 overflow check in extract_range_from_binary_1 useless? Aldy Hernandez
2018-06-13 11:42 ` Richard Biener
2018-07-05 22:06 ` Jeff Law
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