RE: [PATCH]middle-end: inspect all exits for additional annotations for loop.

[Tamar Christina <Tamar.Christina@arm.com>]

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> 
> I think this isn't entirely good.  For simple cases for
> do {} while the condition ends up in the latch while for while () {}
> loops it ends up in the header.  In your case the latch isn't empty
> so it doesn't end up with the conditional.
> 
> I think your patch is OK to the point of looking at all loop exit
> sources but you should elide the special-casing of header and
> latch since it's really only exit conditionals that matter.
> 

That makes sense, since in both cases the edges are in the respective
blocks.  Should have thought about it more.

So how about this one.

Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.

Ok for master?

Thanks,
Tamar

gcc/ChangeLog:

	* tree-cfg.cc (replace_loop_annotate): Inspect loop edges for annotations.

gcc/testsuite/ChangeLog:

	* gcc.dg/vect/vect-novect_gcond.c: New test.

--- inline copy of patch ---

diff --git a/gcc/testsuite/gcc.dg/vect/vect-novect_gcond.c b/gcc/testsuite/gcc.dg/vect/vect-novect_gcond.c
new file mode 100644
index 0000000000000000000000000000000000000000..01e69cbef9d51b234c08a400c78dc078d53252f1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-novect_gcond.c
@@ -0,0 +1,39 @@
+/* { dg-add-options vect_early_break } */
+/* { dg-require-effective-target vect_early_break_hw } */
+/* { dg-require-effective-target vect_int } */
+/* { dg-additional-options "-O3" } */
+
+/* { dg-final { scan-tree-dump-not "LOOP VECTORIZED" "vect" } } */
+
+#include "tree-vect.h"
+
+#define N 306
+#define NEEDLE 136
+
+int table[N];
+
+__attribute__ ((noipa))
+int foo (int i, unsigned short parse_tables_n)
+{
+  parse_tables_n >>= 9;
+  parse_tables_n += 11;
+#pragma GCC novector
+  while (i < N && parse_tables_n--)
+    table[i++] = 0;
+
+  return table[NEEDLE];
+}
+
+int main ()
+{
+  check_vect ();
+
+#pragma GCC novector
+  for (int j = 0; j < N; j++)
+    table[j] = -1;
+
+  if (foo (0, 0xFFFF) != 0)
+    __builtin_abort ();
+
+  return 0;
+}
diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc
index cdd439fe7506e7bc33654ffa027b493f23d278ac..bdffc3b4ed277724e81b7dd67fe7966e8ece0c13 100644
--- a/gcc/tree-cfg.cc
+++ b/gcc/tree-cfg.cc
@@ -320,12 +320,9 @@ replace_loop_annotate (void)
 
   for (auto loop : loops_list (cfun, 0))
     {
-      /* First look into the header.  */
-      replace_loop_annotate_in_block (loop->header, loop);
-
-      /* Then look into the latch, if any.  */
-      if (loop->latch)
-	replace_loop_annotate_in_block (loop->latch, loop);
+      /* Check all exit source blocks for annotations.  */
+      for (auto e : get_loop_exit_edges (loop))
+	replace_loop_annotate_in_block (e->src, loop);
 
       /* Push the global flag_finite_loops state down to individual loops.  */
       loop->finite_p = flag_finite_loops;

[-- Attachment #2: rb18267.patch --]
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diff --git a/gcc/testsuite/gcc.dg/vect/vect-novect_gcond.c b/gcc/testsuite/gcc.dg/vect/vect-novect_gcond.c
new file mode 100644
index 0000000000000000000000000000000000000000..01e69cbef9d51b234c08a400c78dc078d53252f1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-novect_gcond.c
@@ -0,0 +1,39 @@
+/* { dg-add-options vect_early_break } */
+/* { dg-require-effective-target vect_early_break_hw } */
+/* { dg-require-effective-target vect_int } */
+/* { dg-additional-options "-O3" } */
+
+/* { dg-final { scan-tree-dump-not "LOOP VECTORIZED" "vect" } } */
+
+#include "tree-vect.h"
+
+#define N 306
+#define NEEDLE 136
+
+int table[N];
+
+__attribute__ ((noipa))
+int foo (int i, unsigned short parse_tables_n)
+{
+  parse_tables_n >>= 9;
+  parse_tables_n += 11;
+#pragma GCC novector
+  while (i < N && parse_tables_n--)
+    table[i++] = 0;
+
+  return table[NEEDLE];
+}
+
+int main ()
+{
+  check_vect ();
+
+#pragma GCC novector
+  for (int j = 0; j < N; j++)
+    table[j] = -1;
+
+  if (foo (0, 0xFFFF) != 0)
+    __builtin_abort ();
+
+  return 0;
+}
diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc
index cdd439fe7506e7bc33654ffa027b493f23d278ac..bdffc3b4ed277724e81b7dd67fe7966e8ece0c13 100644
--- a/gcc/tree-cfg.cc
+++ b/gcc/tree-cfg.cc
@@ -320,12 +320,9 @@ replace_loop_annotate (void)
 
   for (auto loop : loops_list (cfun, 0))
     {
-      /* First look into the header.  */
-      replace_loop_annotate_in_block (loop->header, loop);
-
-      /* Then look into the latch, if any.  */
-      if (loop->latch)
-	replace_loop_annotate_in_block (loop->latch, loop);
+      /* Check all exit source blocks for annotations.  */
+      for (auto e : get_loop_exit_edges (loop))
+	replace_loop_annotate_in_block (e->src, loop);
 
       /* Push the global flag_finite_loops state down to individual loops.  */
       loop->finite_p = flag_finite_loops;