Re: [PATCH] Set bound/cmp/control for until wrap loop.

[guojiufu <guojiufu@linux.ibm.com>]

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  <guojiufu@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  <guojiufu@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;
> @@ -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);
> +  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" } } */