gcc/

	Backport from trunk r235269.
	2016-04-20  Bin Cheng  <bin.cheng@arm.com>

	* tree-scalar-evolution.c (interpret_rhs_expr): Handle BIT_AND_EXPR.

	gcc/testsuite/
	Backport from trunk r235269.
	2016-04-20  Bin Cheng  <bin.cheng@arm.com>

	* gcc.dg/tree-ssa/scev-11.c: New test.
	* gcc.dg/tree-ssa/scev-12.c: New test.

Change-Id: I7498c033cf77b8ab43ea155d599e603ffec63232

3 files changed, 88 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/scev-11.c b/gcc/testsuite/gcc.dg/tree-ssa/scev-11.c
new file mode 100644
index 00000000000..a7181b2208b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/scev-11.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-ivopts-details" } */
+
+int a[128];
+extern int b[];
+
+int bar (int *);
+
+int
+foo (int n)
+{
+  int i;
+
+  for (i = 0; i < n; i++)
+    {
+      unsigned char uc = (unsigned char)i;
+      a[i] = i;
+      b[uc] = 0;
+    }
+
+  bar (a);
+  return 0;
+}
+
+/* Address of array reference to b is scev.  */
+/* { dg-final { scan-tree-dump-times "use \[0-9\]\n  address" 2 "ivopts" } } */
+
+
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/scev-12.c b/gcc/testsuite/gcc.dg/tree-ssa/scev-12.c
new file mode 100644
index 00000000000..6915ba8b31d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/scev-12.c
@@ -0,0 +1,30 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-ivopts-details" } */
+
+int a[128];
+extern int b[];
+
+int bar (int *);
+
+int
+foo (int x, int n)
+{
+  int i;
+
+  for (i = 0; i < n; i++)
+    {
+      unsigned char uc = (unsigned char)i;
+      if (x)
+	a[i] = i;
+      b[uc] = 0;
+    }
+
+  bar (a);
+  return 0;
+}
+
+/* Address of array reference to b is not scev.  */
+/* { dg-final { scan-tree-dump-times "use \[0-9\]\n  address" 1 "ivopts" } } */
+
+
+
diff --git a/gcc/tree-scalar-evolution.c b/gcc/tree-scalar-evolution.c
index 88a0eaaa82d..d6f2a2fba14 100644
--- a/gcc/tree-scalar-evolution.c
+++ b/gcc/tree-scalar-evolution.c
@@ -1937,6 +1937,36 @@ interpret_rhs_expr (struct loop *loop, gimple *at_stmt,
       res = chrec_convert (type, chrec1, at_stmt);
       break;
 
+    case BIT_AND_EXPR:
+      /* Given int variable A, handle A&0xffff as (int)(unsigned short)A.
+	 If A is SCEV and its value is in the range of representable set
+	 of type unsigned short, the result expression is a (no-overflow)
+	 SCEV.  */
+      res = chrec_dont_know;
+      if (tree_fits_uhwi_p (rhs2))
+	{
+	  int precision;
+	  unsigned HOST_WIDE_INT val = tree_to_uhwi (rhs2);
+
+	  val ++;
+	  /* Skip if value of rhs2 wraps in unsigned HOST_WIDE_INT or
+	     it's not the maximum value of a smaller type than rhs1.  */
+	  if (val != 0
+	      && (precision = exact_log2 (val)) > 0
+	      && (unsigned) precision < TYPE_PRECISION (TREE_TYPE (rhs1)))
+	    {
+	      tree utype = build_nonstandard_integer_type (precision, 1);
+
+	      if (TYPE_PRECISION (utype) < TYPE_PRECISION (TREE_TYPE (rhs1)))
+		{
+		  chrec1 = analyze_scalar_evolution (loop, rhs1);
+		  chrec1 = chrec_convert (utype, chrec1, at_stmt);
+		  res = chrec_convert (TREE_TYPE (rhs1), chrec1, at_stmt);
+		}
+	    }
+	}
+      break;
+
     default:
       res = chrec_dont_know;
       break;