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

[guojiufu via Gcc-patches]

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;
@@ -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" } } */