On January 24, 2019 8:19:11 PM GMT+01:00, Jakub Jelinek <ja...@redhat.com>
wrote:
>On Wed, Jan 23, 2019 at 09:23:53AM +0100, Richard Biener wrote:
>> On Tue, 22 Jan 2019, Jakub Jelinek wrote:
>>
>> > Hi!
>> >
>> > SCEV can analyze not just integral/pointer IVs, but (scalar) float
>ones as
>> > well. Calling build_int_cst on such types results in ICE,
>build_zero_cst
>> > works. Though the loop invariant PHI IVs, if we represent them as
>using
>> > +0.0 step, aren't correct if honoring signed zeros, as + 0.0 will
>make
>> > a +0.0 out of -0.0.
>> >
>> > Bootstrapped/regtested on {x86_64,i686,powerpc64{,le}}-linux, ok
>for trunk?
>>
>> OK.
>
>Thinking about it, if we honor SNaNs, we should punt too, even if we
>are not
>honoring signed zeros, because sNaN + 0.0 artificially added there will
>raise an exception, where previously the code could not raise it.
>
>Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok
>for
>trunk?
OK.
Richard.
>2019-01-24 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/88964
> * gimple-loop-interchange.cc (loop_cand::analyze_induction_var): Also
> punt if HONOR_SNANS (chrec).
>
>--- gcc/gimple-loop-interchange.cc.jj 2019-01-23 09:34:53.739433699
>+0100
>+++ gcc/gimple-loop-interchange.cc 2019-01-23 12:53:35.215848790 +0100
>@@ -690,8 +690,8 @@ loop_cand::analyze_induction_var (tree v
> {
> /* Punt on floating point invariants if honoring signed zeros,
> representing that as + 0.0 would change the result if init
>- is -0.0. */
>- if (HONOR_SIGNED_ZEROS (chrec))
>+ is -0.0. Similarly for SNaNs it can raise exception. */
>+ if (HONOR_SIGNED_ZEROS (chrec) || HONOR_SNANS (chrec))
> return false;
> struct induction *iv = XCNEW (struct induction);
> iv->var = var;
>
>
> Jakub
