Re: Determine more IVs to be non-overflowing

> > Yeah, I think the other comment should be adjusted accordingly. I > > didn't remember we have that one extra bit either ... ;) (given wide-ints > > have unsigned variants of ops I wonder if it is really necessary, but who > > knows - the wide-int rep w/o a sign is really sth odd and I blame

Re: Determine more IVs to be non-overflowing

> On Wed, 6 Jul 2016, Jan Hubicka wrote: > > > > Jan Hubicka writes: > > > > > > > Bootstrapped/regtested x86_64-linux, OK? > > > > > > > > * gcc.dg/tree-ssa/scev-14.c: new testcase. > > > > > > FAIL: gcc.dg/tree-ssa/scev-14.c scan-tree-dump-not ivopts "Overflowness >

Re: Determine more IVs to be non-overflowing

On Wed, 6 Jul 2016, Jan Hubicka wrote: > > Jan Hubicka writes: > > > > > Bootstrapped/regtested x86_64-linux, OK? > > > > > > * gcc.dg/tree-ssa/scev-14.c: new testcase. > > > > FAIL: gcc.dg/tree-ssa/scev-14.c scan-tree-dump-not ivopts "Overflowness > > wrto loop

Re: Determine more IVs to be non-overflowing

> Jan Hubicka writes: > > > Bootstrapped/regtested x86_64-linux, OK? > > > > * gcc.dg/tree-ssa/scev-14.c: new testcase. > > FAIL: gcc.dg/tree-ssa/scev-14.c scan-tree-dump-not ivopts "Overflowness wrto > loop niter:\tOverflow" Aha, this is wrong version of testcase. The

Re: Determine more IVs to be non-overflowing

Jan Hubicka writes: > Bootstrapped/regtested x86_64-linux, OK? > > * gcc.dg/tree-ssa/scev-14.c: new testcase. FAIL: gcc.dg/tree-ssa/scev-14.c scan-tree-dump-not ivopts "Overflowness wrto loop niter:\tOverflow" $ grep Overflowness scev-14.c.155t.ivopts Overflowness

Re: Determine more IVs to be non-overflowing

Richard Biener writes: > On Tue, 5 Jul 2016, Jan Hubicka wrote: > >> > On Tue, 5 Jul 2016, Richard Biener wrote: >> > >> > >given widest_int has only precision of TImode on x86_64? >> > >> > Is that the case? The comments say: >> > >> > It is really finite precision

Re: Determine more IVs to be non-overflowing

On Tue, 5 Jul 2016, Jan Hubicka wrote: > > On Tue, 5 Jul 2016, Richard Biener wrote: > > > > >given widest_int has only precision of TImode on x86_64? > > > > Is that the case? The comments say: > > > > It is really finite precision math where the precision is 4 times the > > size of

Re: Determine more IVs to be non-overflowing

> On Tue, 5 Jul 2016, Richard Biener wrote: > > >given widest_int has only precision of TImode on x86_64? > > Is that the case? The comments say: > > It is really finite precision math where the precision is 4 times the > size of the largest integer that the target port can represent.

Re: Determine more IVs to be non-overflowing

> > This can overflow for __uint128_t IV iterating to UINT128_MAX I think > given widest_int has only precision of TImode on x86_64? An > after-the-fact check like > >if (nit == 0) > return true; > > does the trick I guess. OK, I suppose we need to review niter and related code for

Re: Determine more IVs to be non-overflowing

On Tue, 5 Jul 2016, Richard Biener wrote: given widest_int has only precision of TImode on x86_64? Is that the case? The comments say: It is really finite precision math where the precision is 4 times the size of the largest integer that the target port can represent. And the

Re: Determine more IVs to be non-overflowing

On Sun, 3 Jul 2016, Jan Hubicka wrote: > Hi, > this is updated version of patch. I finally convinced myself to read bit of > wide-int.h and learnt some new things, like that they exists in multiple > precisions. I always tought of wide-int as wider version of HOST_WIDE_INT > that > can hold all

Re: Determine more IVs to be non-overflowing

Hi, this is updated version of patch. I finally convinced myself to read bit of wide-int.h and learnt some new things, like that they exists in multiple precisions. I always tought of wide-int as wider version of HOST_WIDE_INT that can hold all of target data types with not-so handy API because

Re: Determine more IVs to be non-overflowing

> > Index: tree-scalar-evolution.c > > === > > --- tree-scalar-evolution.c (revision 237856) > > +++ tree-scalar-evolution.c (working copy) > > @@ -280,6 +280,7 @@ along with GCC; see the file COPYING3. > > #include "params.h" > >

Re: Determine more IVs to be non-overflowing

On Thu, 30 Jun 2016, Jan Hubicka wrote: > Hi, > i sent the email before, but it seems it never left my machine. Sorry for > possible duplicates. This is updated version which does not overflow (by > capping nit), but still using widest_int for the calculatoins. It seems more > readable to do so

Re: Determine more IVs to be non-overflowing

Hi, i sent the email before, but it seems it never left my machine. Sorry for possible duplicates. This is updated version which does not overflow (by capping nit), but still using widest_int for the calculatoins. It seems more readable to do so than using wi:add/wi:mult/wi:lt and overflow

Re: Determine more IVs to be non-overflowing

Hi, after some exprimentation I am re-testing the following version. wide_int variant seemed ugly. Here I simply cap nit to be in range of the type and then the widest_int calculation ought to be safe. What do you think? Perhaps I need to use signs of STEP and BASE type just in the case some

Re: Determine more IVs to be non-overflowing

On Wed, 29 Jun 2016, Jan Hubicka wrote: > > + if (!get_max_loop_iterations (loop, )) > > +/* 10GHz CPU runing one cycle loop will reach 2^60 iterations in 260 > > + years. I won't live long enough to be forced to fix the > > + miscompilation. Having the limit here will let us

Re: Determine more IVs to be non-overflowing

> + if (!get_max_loop_iterations (loop, )) > +/* 10GHz CPU runing one cycle loop will reach 2^60 iterations in 260 > + years. I won't live long enough to be forced to fix the > + miscompilation. Having the limit here will let us to consider > + 64bit IVs with base 0 and

Re: Determine more IVs to be non-overflowing

On Mon, 27 Jun 2016, Jan Hubicka wrote: > Hi, > this patch makes simple_iv to determine more often that IV can not overflow. > First I commonized the logic in simple_iv with nowrap_type_p because it tests > the same. Second I added iv_can_overflow_p which uses known upper bound on > number of

Determine more IVs to be non-overflowing

Hi, this patch makes simple_iv to determine more often that IV can not overflow. First I commonized the logic in simple_iv with nowrap_type_p because it tests the same. Second I added iv_can_overflow_p which uses known upper bound on number of iteration to see if the IV calculation can overflow.