[PATCH] Fix up reduction-1{1,2} testcases (PR middle-end/68221)

[Jakub Jelinek]

Hi!

If C/C++ array section reductions have non-zero (positive) bias, it is
implemented by declaring a smaller private array and subtracting the bias
from the start of the private array (because valid code may only dereference
elements from bias onwards).  But, this isn't something that is kosher in
C/C++ pointer arithmetics and the alias oracle seems to get upset on that.
So, the following patch fixes that by performing the subtraction on integral
type instead of p+ -bias.

Bootstrapped/regtested on x86_64-linux and i686-linux, committed to trunk.

2015-11-20  Jakub Jelinek  <ja...@redhat.com>

        PR middle-end/68221
        * omp-low.c (lower_rec_input_clauses): If C/C++ array reduction
        has non-zero bias, subtract it in integer type instead of
        pointer plus of negated bias.

        * testsuite/libgomp.c/reduction-11.c: Remove xfail.
        * testsuite/libgomp.c/reduction-12.c: Likewise.
        * testsuite/libgomp.c++/reduction-11.C: Likewise.
        * testsuite/libgomp.c++/reduction-12.C: Likewise.

--- gcc/omp-low.c.jj    2015-11-20 12:56:17.000000000 +0100
+++ gcc/omp-low.c       2015-11-20 13:44:29.080374051 +0100
@@ -4444,11 +4444,13 @@ lower_rec_input_clauses (tree clauses, g
 
              if (!integer_zerop (bias))
                {
-                 bias = fold_convert_loc (clause_loc, sizetype, bias);
-                 bias = fold_build1_loc (clause_loc, NEGATE_EXPR,
-                                         sizetype, bias);
-                 x = fold_build2_loc (clause_loc, POINTER_PLUS_EXPR,
-                                      TREE_TYPE (x), x, bias);
+                 bias = fold_convert_loc (clause_loc, pointer_sized_int_node,
+                                          bias);
+                 yb = fold_convert_loc (clause_loc, pointer_sized_int_node,
+                                        x);
+                 yb = fold_build2_loc (clause_loc, MINUS_EXPR,
+                                       pointer_sized_int_node, yb, bias);
+                 x = fold_convert_loc (clause_loc, TREE_TYPE (x), yb);
                  yb = create_tmp_var (ptype, name);
                  gimplify_assign (yb, x, ilist);
                  x = yb;
--- libgomp/testsuite/libgomp.c/reduction-11.c.jj       2015-11-05 
16:03:53.000000000 +0100
+++ libgomp/testsuite/libgomp.c/reduction-11.c  2015-11-20 13:38:24.448520879 
+0100
@@ -1,4 +1,4 @@
-/* { dg-do run { xfail *-*-* } } */
+/* { dg-do run } */
 
 char z[10] = { 0 };
 
--- libgomp/testsuite/libgomp.c/reduction-12.c.jj       2015-11-05 
16:03:53.000000000 +0100
+++ libgomp/testsuite/libgomp.c/reduction-12.c  2015-11-20 13:38:34.565378078 
+0100
@@ -1,4 +1,4 @@
-/* { dg-do run { xfail *-*-* } } */
+/* { dg-do run } */
 
 struct A { int t; };
 struct B { char t; };
--- libgomp/testsuite/libgomp.c++/reduction-11.C.jj     2015-11-05 
16:03:53.000000000 +0100
+++ libgomp/testsuite/libgomp.c++/reduction-11.C        2015-11-20 
13:37:53.921951766 +0100
@@ -1,4 +1,4 @@
-// { dg-do run { xfail *-*-* } }
+// { dg-do run }
 
 char z[10] = { 0 };
 
--- libgomp/testsuite/libgomp.c++/reduction-12.C.jj     2015-11-05 
16:03:53.000000000 +0100
+++ libgomp/testsuite/libgomp.c++/reduction-12.C        2015-11-20 
13:38:03.983809741 +0100
@@ -1,4 +1,4 @@
-// { dg-do run { xfail *-*-* } }
+// { dg-do run }
 
 template <typename T>
 struct A

        Jakub