[Bug middle-end/35307] Missing Simplication for div op

2017-06-26 Thread segher at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=35307

Segher Boessenkool  changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 CC||segher at gcc dot gnu.org
 Resolution|--- |INVALID

--- Comment #4 from Segher Boessenkool  ---
Cannot work in the general case.

[Bug middle-end/35307] Missing Simplication for div op

2008-02-26 Thread segher at kernel dot crashing dot org 


--- Comment #3 from segher at kernel dot crashing dot org  2008-02-26 16:16 
---
> > Not equivalent in the presence of overflow.
> 
> You mean defined overflow :).

No, I mean overflow.

Let's assume int is 16-bit (just to keep the numbers smallish);
now take i=1, j=1000, k=1000.  i/j/k is perfectly well-defined,
but i/(j*k) overflows in the j*k computation.


Segher


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segher at kernel dot crashing dot org changed:

   What|Removed |Added

 CC||segher at kernel dot
   ||crashing dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35307

[Bug middle-end/35307] Missing Simplication for div op

2008-02-24 Thread rguenth at gcc dot gnu dot org 


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rguenth at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
 Ever Confirmed|0   |1
   Last reconfirmed|-00-00 00:00:00 |2008-02-24 22:16:29
   date||
Version|unknown |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35307

[Bug middle-end/35307] Missing Simplication for div op

2008-02-23 Thread pinskia at gcc dot gnu dot org 


--- Comment #2 from pinskia at gcc dot gnu dot org  2008-02-23 20:00 ---
(In reply to comment #1)
> Not equivalent in the presence of overflow.

You mean defined overflow :).


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pinskia at gcc dot gnu dot org changed:

   What|Removed |Added

   Severity|normal  |enhancement
   Keywords||missed-optimization


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35307

[Bug middle-end/35307] Missing Simplication for div op

2008-02-23 Thread segher at kernel dot crashing dot org 


--- Comment #1 from segher at kernel dot crashing dot org  2008-02-23 19:57 
---
Not equivalent in the presence of overflow.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35307