Account for high/lo_sum simplification with displacements

gcc/
	* simplify-rtx.c (simplify_replace_fn_rtx): Simplify (lo_sum
	(high x) y) to y if x and y have the same base.

gcc/testsuite/
	* gcc.c-torture/compile/20150108.c: New test.

From-SVN: r219729

gcc/ChangeLog

+2015-01-16  Robert Suchanek  <robert.suchanek@imgtec.com>
+
+	* simplify-rtx.c (simplify_replace_fn_rtx): Simplify (lo_sum
+	(high x) y) to y if x and y have the same base.
+
 2015-01-16  James Greenhalgh  <james.greenhalgh@arm.com>
 
 	* config/arm/cortex-a57.md: New.

gcc/simplify-rtx.c

@@ -539,9 +539,15 @@ simplify_replace_fn_rtx (rtx x, const_rtx old_rtx,
 	  op0 = simplify_replace_fn_rtx (XEXP (x, 0), old_rtx, fn, data);
 	  op1 = simplify_replace_fn_rtx (XEXP (x, 1), old_rtx, fn, data);
 
-	  /* (lo_sum (high x) x) -> x  */
-	  if (GET_CODE (op0) == HIGH && rtx_equal_p (XEXP (op0, 0), op1))
-	    return op1;
+	  /* (lo_sum (high x) y) -> y where x and y have the same base.  */
+	  if (GET_CODE (op0) == HIGH)
+	    {
+	      rtx base0, base1, offset0, offset1;
+	      split_const (XEXP (op0, 0), &base0, &offset0);
+	      split_const (op1, &base1, &offset1);
+	      if (rtx_equal_p (base0, base1))
+		return op1;
+	    }
 
 	  if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
 	    return x;

gcc/testsuite/ChangeLog

+2015-01-16  Robert Suchanek  <robert.suchanek@imgtec.com>
+
+	* gcc.c-torture/compile/20150108.c: New test.
+
 2015-01-16  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gcc.target/visium: New directory.

gcc/testsuite/gcc.c-torture/compile/20150108.c

+long long a[10];
+long long b, c, d, k, m, n, o, p, q, r, s, t, u, v, w;
+int e, f, g, h, i, j, l, x;
+
+int fn1 () {
+  for (; x; x++)
+    if (x & 1)
+      s = h | g;
+    else
+      s = f | e;
+  l = ~0;
+  m = 1 | k;
+  n = i;
+  o = j;
+  p = f | e;
+  q = h | g;
+  w = d | c | a[1];
+  t = c;
+  v = b | c;
+  u = v;
+  r = b | a[4];
+  return e;