[patch] Fix PR tree-optimization/40254 - bug in data-refs analysis for basic blocks

[Ira Rosen <IRAR at il dot ibm dot com>]

Hi,

This patch fixes a bug in data-refs analysis for basic blocks: the
data-ref's offset should be taken into account.

Bootstrapped with vectorization enabled on powerpc64-suse-linux, tested on
x86_64-suse-linux.

O.K. for mainline?

Thanks,
Ira


ChangeLog:

      PR tree-optimization/40254
      * tree-data-ref.c (dr_analyze_innermost): Take POFFSET into account
      in analysis of basic blocks.

testsuite/ChangeLog:

      PR tree-optimization/40254
      * gcc.dg/vect/pr40254.c: New test.


Index: tree-data-ref.c
===================================================================
--- tree-data-ref.c     (revision 147938)
+++ tree-data-ref.c     (working copy)
@@ -718,17 +718,26 @@ dr_analyze_innermost (struct data_refere
       base_iv.no_overflow = true;
     }

-  if (!poffset || !in_loop)
+  if (!poffset)
     {
       offset_iv.base = ssize_int (0);
       offset_iv.step = ssize_int (0);
     }
-  else if (!simple_iv (loop, loop_containing_stmt (stmt),
-                      poffset, &offset_iv, false))
+  else
     {
-      if (dump_file && (dump_flags & TDF_DETAILS))
-       fprintf (dump_file, "failed: evolution of offset is not
affine.\n");
-      return false;
+      if (!in_loop)
+        {
+          offset_iv.base = poffset;
+          offset_iv.step = ssize_int (0);
+        }
+      else if (!simple_iv (loop, loop_containing_stmt (stmt),
+                           poffset, &offset_iv, false))
+        {
+          if (dump_file && (dump_flags & TDF_DETAILS))
+            fprintf (dump_file, "failed: evolution of offset is not"
+                                " affine.\n");
+          return false;
+        }
     }

   init = ssize_int (pbitpos / BITS_PER_UNIT);
Index: testsuite/gcc.dg/vect/pr40254.c
===================================================================
--- testsuite/gcc.dg/vect/pr40254.c     (revision 0)
+++ testsuite/gcc.dg/vect/pr40254.c     (revision 0)
@@ -0,0 +1,39 @@
+#include <stdlib.h>
+#include <stdarg.h>
+#include "tree-vect.h"
+
+struct s
+{
+  int *x;
+  int x1;
+  int x2;
+  int x3;
+  int *y;
+};
+
+struct s arr[64] __attribute__ ((__aligned__(__BIGGEST_ALIGNMENT__)));
+
+__attribute__ ((noinline)) void
+foo (int i, int *in_x, int *in_y)
+{
+  arr[i].x = in_x;
+  arr[i].y = in_y;
+}
+
+int
+main (void)
+{
+  int a, b;
+
+  check_vect ();
+
+  foo (5, &a, &b);
+
+  if (arr[5].x != &a || arr[5].y != &b)
+    abort ();
+
+  return 0;
+}
+
+/* { dg-final { cleanup-tree-dump "vect" } } */
+