On Mon, 30 Aug 2021, guojiufu wrote:
> On 2021-08-30 14:15, Jiufu Guo wrote:
> > Hi,
> >
> > In patch r12-3136, niter->control, niter->bound and niter->cmp are
> > derived from number_of_iterations_lt. While for 'until wrap condition',
> > the calculation in number_of_iterations_lt is not align the requirements
> > on the define of them and requirements in determine_exit_conditions.
> >
> > This patch calculate niter->control, niter->bound and niter->cmp in
> > number_of_iterations_until_wrap.
> >
> > The ICEs in the PR are pass with this patch.
> > Bootstrap and reg-tests pass on ppc64/ppc64le and x86.
> > Is this ok for trunk?
> >
> > BR.
> > Jiufu Guo
> >
> Add ChangeLog:
> gcc/ChangeLog:
>
> 2021-08-30 Jiufu Guo <guoji...@linux.ibm.com>
>
> PR tree-optimization/102087
> * tree-ssa-loop-niter.c (number_of_iterations_until_wrap):
> Set bound/cmp/control for niter.
>
> gcc/testsuite/ChangeLog:
>
> 2021-08-30 Jiufu Guo <guoji...@linux.ibm.com>
>
> PR tree-optimization/102087
> * gcc.dg/vect/pr101145_3.c: Update tests.
> * gcc.dg/pr102087.c: New test.
>
> > ---
> > gcc/tree-ssa-loop-niter.c | 14 +++++++++++++-
> > gcc/testsuite/gcc.dg/pr102087.c | 25 +++++++++++++++++++++++++
> > gcc/testsuite/gcc.dg/vect/pr101145_3.c | 4 +++-
> > 3 files changed, 41 insertions(+), 2 deletions(-)
> > create mode 100644 gcc/testsuite/gcc.dg/pr102087.c
> >
> > diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c
> > index 7af92d1c893..747f04d3ce0 100644
> > --- a/gcc/tree-ssa-loop-niter.c
> > +++ b/gcc/tree-ssa-loop-niter.c
> > @@ -1482,7 +1482,7 @@ number_of_iterations_until_wrap (class loop *,
> > tree type, affine_iv *iv0,
> > affine_iv *iv1, class tree_niter_desc *niter)
> > {
> > tree niter_type = unsigned_type_for (type);
> > - tree step, num, assumptions, may_be_zero;
> > + tree step, num, assumptions, may_be_zero, span;
> > wide_int high, low, max, min;
> >
> > may_be_zero = fold_build2 (LE_EXPR, boolean_type_node, iv1->base,
> > iv0->base);
> > @@ -1513,6 +1513,8 @@ number_of_iterations_until_wrap (class loop *,
> > tree type, affine_iv *iv0,
> > low = wi::to_wide (iv0->base);
> > else
> > low = min;
> > +
> > + niter->control = *iv1;
> > }
> > /* {base, -C} < n. */
> > else if (tree_int_cst_sign_bit (iv0->step) && integer_zerop
> > (iv1->step))
> > @@ -1533,6 +1535,8 @@ number_of_iterations_until_wrap (class loop *,
> > tree type, affine_iv *iv0,
> > high = wi::to_wide (iv1->base);
> > else
> > high = max;
> > +
> > + niter->control = *iv0;
> > }
> > else
> > return false;
it looks like the above two should already be in effect from the
caller (guarding with integer_nozerop)?
> > @@ -1556,6 +1560,14 @@ number_of_iterations_until_wrap (class loop *,
> > tree type, affine_iv *iv0,
> > niter->assumptions, assumptions);
> >
> > niter->control.no_overflow = false;
> > + niter->control.base = fold_build2 (MINUS_EXPR, niter_type,
> > + niter->control.base,
> > niter->control.step);
how do we know IVn - STEP doesn't already wrap? A comment might be
good to explain you're turning the simplified exit condition into
{ IVbase - STEP, +, STEP } != niter * STEP + (IVbase - STEP)
which, when mathematically looking at it makes me wonder why there's
the seemingly redundant '- STEP' term? Also is NE_EXPR really
correct since STEP might be not 1? Only for non equality compares
the '- STEP' should matter?
Richard.
> > + span = fold_build2 (MULT_EXPR, niter_type, niter->niter,
> > + fold_convert (niter_type, niter->control.step));
> > + niter->bound = fold_build2 (PLUS_EXPR, niter_type, span,
> > + fold_convert (niter_type, niter->control.base));
> > + niter->bound = fold_convert (type, niter->bound);
> > + niter->cmp = NE_EXPR;
> >
> > return true;
> > }
> > diff --git a/gcc/testsuite/gcc.dg/pr102087.c
> > b/gcc/testsuite/gcc.dg/pr102087.c
> > new file mode 100644
> > index 00000000000..ef1f9f5cba9
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/pr102087.c
> > @@ -0,0 +1,25 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O3" } */
> > +
> > +unsigned __attribute__ ((noinline))
> > +foo (int *__restrict__ a, int *__restrict__ b, unsigned l, unsigned n)
> > +{
> > + while (n < ++l)
> > + *a++ = *b++ + 1;
> > + return l;
> > +}
> > +
> > +volatile int a[1];
> > +unsigned b;
> > +int c;
> > +
> > +int
> > +check ()
> > +{
> > + int d;
> > + for (; b > 1; b++)
> > + for (c = 0; c < 2; c++)
> > + for (d = 0; d < 2; d++)
> > + a[0];
> > + return 0;
> > +}
> > diff --git a/gcc/testsuite/gcc.dg/vect/pr101145_3.c
> > b/gcc/testsuite/gcc.dg/vect/pr101145_3.c
> > index 99289afec0b..40cb0240aaa 100644
> > --- a/gcc/testsuite/gcc.dg/vect/pr101145_3.c
> > +++ b/gcc/testsuite/gcc.dg/vect/pr101145_3.c
> > @@ -1,5 +1,6 @@
> > /* { dg-require-effective-target vect_int } */
> > /* { dg-options "-O3 -fdump-tree-vect-details" } */
> > +
> > #define TYPE int *
> > #define MIN ((TYPE)0)
> > #define MAX ((TYPE)((long long)-1))
> > @@ -10,4 +11,5 @@
> >
> > #include "pr101145.inc"
> >
> > -/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 2 "vect" } } */
> > +/* pointer size may not be vectorized, checking niter is ok. */
> > +/* { dg-final { scan-tree-dump "Symbolic number of iterations is" "vect" }
> > } */
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
