Re: [PATCH] Fixup nb_iterations_upper_bound adjustment for vectorized loops

[Ilya Enkovich <enkovich dot gnu at gmail dot com>]

On 27 Apr 16:05, Richard Biener wrote:
> >>
> >> I'd like to see testcases covering the corner-cases - have them have
> >> upper bound estimates by adjusting known array sizes and also cover
> >> the case of peeling for gaps.
> >
> > OK, I'll make more tests.
> > Thanks,
> > Ilya
> >
> >>
> >> Richard.
> >>

Could you please look at new tests?  I added one simple case with
known array size and similar tests with a peeling for gaps w/ and
w/o vector iteration peeled.

Checked new tests with RUNTESTFLAGS="vect.exp=vect-nb-iter-ub-* --target_board=unix{-m32,}
on x86_64-pc-linux-gnu.  OK for trunk?

Thanks,
Ilya
--
gcc/

2016-04-28  Ilya Enkovich  <ilya.enkovich@intel.com>

	* tree-vect-loop.c (vect_transform_loop): Fix
	nb_iterations_upper_bound computation for vectorized loop.

gcc/testsuite/

2016-04-28  Ilya Enkovich  <ilya.enkovich@intel.com>

	* gcc.target/i386/vect-unpack-2.c (avx512bw_test): Avoid
	optimization of vector loop.
	* gcc.target/i386/vect-unpack-3.c: New test.
	* gcc.dg/vect/vect-nb-iter-ub-1.c: New test.
	* gcc.dg/vect/vect-nb-iter-ub-2.c: New test.
	* gcc.dg/vect/vect-nb-iter-ub-3.c: New test.


diff --git a/gcc/testsuite/gcc.dg/vect/vect-nb-iter-ub-1.c b/gcc/testsuite/gcc.dg/vect/vect-nb-iter-ub-1.c
new file mode 100644
index 0000000..b7504a8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-nb-iter-ub-1.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-mavx512bw -fdump-tree-cunroll-details" { target { i?86-*-* x86_64-*-* } } } */
+
+int ii[127];
+char cc[127];
+
+void
+foo (int s)
+{
+  int i;
+   for (i = 0; i < s; i++)
+     ii[i] = (int) cc[i];
+}
+
+/* { dg-final { scan-tree-dump "vectorized 1 loops" "vect" { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-tree-dump "loop turned into non-loop; it never loops" "cunroll" { target { i?86-*-* x86_64-*-* } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/vect-nb-iter-ub-2.c b/gcc/testsuite/gcc.dg/vect/vect-nb-iter-ub-2.c
new file mode 100644
index 0000000..5332636
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-nb-iter-ub-2.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-mavx512bw -fdump-tree-cunroll-details" { target { i?86-*-* x86_64-*-* } } } */
+
+int ii[128];
+char cc[256];
+
+void
+foo (int s)
+{
+  int i;
+   for (i = 0; i < s; i++)
+     ii[i] = (int) cc[i*2];
+}
+
+/* { dg-final { scan-tree-dump "vectorized 1 loops" "vect" { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-tree-dump "loop turned into non-loop; it never loops" "cunroll" { target { i?86-*-* x86_64-*-* } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/vect-nb-iter-ub-3.c b/gcc/testsuite/gcc.dg/vect/vect-nb-iter-ub-3.c
new file mode 100644
index 0000000..5610f6a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-nb-iter-ub-3.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-mavx512bw -fdump-tree-cunroll-details" { target { i?86-*-* x86_64-*-* } } } */
+
+int ii[130];
+char cc[258];
+
+void
+foo (int s)
+{
+  int i;
+   for (i = 0; i < s; i++)
+     ii[i] = (int) cc[i*2];
+}
+
+/* { dg-final { scan-tree-dump "vectorized 1 loops" "vect" { target { i?86-*-* x86_64-*-* } } } } */
+/* { dg-final { scan-tree-dump-not "loop turned into non-loop; it never loops" "cunroll" { target { i?86-*-* x86_64-*-* } } } } */
diff --git a/gcc/testsuite/gcc.target/i386/vect-unpack-2.c b/gcc/testsuite/gcc.target/i386/vect-unpack-2.c
index 4825248..51c518e 100644
--- a/gcc/testsuite/gcc.target/i386/vect-unpack-2.c
+++ b/gcc/testsuite/gcc.target/i386/vect-unpack-2.c
@@ -6,19 +6,22 @@
 
 #define N 120
 signed int yy[10000];
+signed char zz[10000];
 
 void
-__attribute__ ((noinline)) foo (signed char s)
+__attribute__ ((noinline,noclone)) foo (int s)
 {
-   signed char i;
+   int i;
    for (i = 0; i < s; i++)
-     yy[i] = (signed int) i;
+     yy[i] = zz[i];
 }
 
 void
 avx512bw_test ()
 {
   signed char i;
+  for (i = 0; i < N; i++)
+    zz[i] = i;
   foo (N);
   for (i = 0; i < N; i++)
     if ( (signed int)i != yy [i] )
diff --git a/gcc/testsuite/gcc.target/i386/vect-unpack-3.c b/gcc/testsuite/gcc.target/i386/vect-unpack-3.c
new file mode 100644
index 0000000..eb8a93e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/vect-unpack-3.c
@@ -0,0 +1,29 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-vect-details -ftree-vectorize -ffast-math -mavx512bw -save-temps" } */
+/* { dg-require-effective-target avx512bw } */
+
+#include "avx512bw-check.h"
+
+#define N 120
+signed int yy[10000];
+
+void
+__attribute__ ((noinline)) foo (signed char s)
+{
+   signed char i;
+   for (i = 0; i < s; i++)
+     yy[i] = (signed int) i;
+}
+
+void
+avx512bw_test ()
+{
+  signed char i;
+  foo (N);
+  for (i = 0; i < N; i++)
+    if ( (signed int)i != yy [i] )
+      abort ();
+}
+
+/* { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" } } */
+/* { dg-final { scan-assembler-not "vpmovsxbw\[ \\t\]+\[^\n\]*%zmm" } } */
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index d813b86..da98211 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -6921,11 +6921,13 @@ vect_transform_loop (loop_vec_info loop_vinfo)
   /* Reduce loop iterations by the vectorization factor.  */
   scale_loop_profile (loop, GCOV_COMPUTE_SCALE (1, vectorization_factor),
 		      expected_iterations / vectorization_factor);
-  loop->nb_iterations_upper_bound
-    = wi::udiv_floor (loop->nb_iterations_upper_bound, vectorization_factor);
   if (LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo)
       && loop->nb_iterations_upper_bound != 0)
     loop->nb_iterations_upper_bound = loop->nb_iterations_upper_bound - 1;
+  loop->nb_iterations_upper_bound
+    = wi::udiv_floor (loop->nb_iterations_upper_bound + 1,
+		      vectorization_factor) - 1;
+
   if (loop->any_estimate)
     {
       loop->nb_iterations_estimate