Hi!
When cp_fold is called on INDIRECT_REF and ARRAY*_REF and any of the
arguments change in the recursive calls, we fail to copy TREE_THIS_VOLATILE
flag.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk/6.2?
2016-06-02 Jakub Jelinek <ja...@redhat.com>
PR c++/71372
* cp-gimplify.c (cp_fold): For INDIRECT_REF, if the folded expression
is INDIRECT_REF or MEM_REF, copy over TREE_READONLY, TREE_SIDE_EFFECTS
and TREE_THIS_VOLATILE flags. For ARRAY_REF and ARRAY_RANGE_REF, copy
over TREE_READONLY, TREE_SIDE_EFFECTS and TREE_THIS_VOLATILE flags
to the newly built tree.
* c-c++-common/pr71372.c: New test.
--- gcc/cp/cp-gimplify.c.jj 2016-05-26 10:38:01.000000000 +0200
+++ gcc/cp/cp-gimplify.c 2016-06-02 10:21:33.903655321 +0200
@@ -2035,7 +2035,16 @@ cp_fold (tree x)
if (op0 == error_mark_node)
x = error_mark_node;
else
- x = fold_build1_loc (loc, code, TREE_TYPE (x), op0);
+ {
+ x = fold_build1_loc (loc, code, TREE_TYPE (x), op0);
+ if (code == INDIRECT_REF
+ && (INDIRECT_REF_P (x) || TREE_CODE (x) == MEM_REF))
+ {
+ TREE_READONLY (x) = TREE_READONLY (org_x);
+ TREE_SIDE_EFFECTS (x) = TREE_SIDE_EFFECTS (org_x);
+ TREE_THIS_VOLATILE (x) = TREE_THIS_VOLATILE (org_x);
+ }
+ }
}
else
x = fold (x);
@@ -2312,7 +2321,12 @@ cp_fold (tree x)
|| op3 == error_mark_node)
x = error_mark_node;
else
- x = build4_loc (loc, code, TREE_TYPE (x), op0, op1, op2, op3);
+ {
+ x = build4_loc (loc, code, TREE_TYPE (x), op0, op1, op2, op3);
+ TREE_READONLY (x) = TREE_READONLY (org_x);
+ TREE_SIDE_EFFECTS (x) = TREE_SIDE_EFFECTS (org_x);
+ TREE_THIS_VOLATILE (x) = TREE_THIS_VOLATILE (org_x);
+ }
}
x = fold (x);
--- gcc/testsuite/c-c++-common/pr71372.c.jj 2016-06-02 10:53:40.994678549
+0200
+++ gcc/testsuite/c-c++-common/pr71372.c 2016-06-02 10:53:04.000000000
+0200
@@ -0,0 +1,14 @@
+/* PR c++/71372 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+void
+foo (volatile int *p, int q)
+{
+ *(volatile int *)p = 0;
+ *(p + (q - q) + 1) = 0;
+ *(p + (q - q) + 2) = 0;
+ *(p + (q - q) + 3) = 0;
+}
+
+/* { dg-final { scan-tree-dump-times " ={v} " 4 "optimized" } } */
Jakub
