>
> Ah, no, of course not. I guess the early out here should be a
> "ignore this match" instead.
Here is updated patch with a testcase I have re-tested on x86_64-linux
and comitted. There are still few divergences left, I will debug them
now.
Again the testcase has extra wrapper in struct d to prevent oracle
giving up earlier via overlaping_range_refs.
Honza
* tree-ssa-alias.c (nonoverlapping_component_refs_p): Do not
give up on bitfields; continue searching for different refs
appearing later.
* gcc.dg/tree-ssa/alias-access-path-6.c: New testcase.
Index: tree-ssa-alias.c
===================================================================
--- tree-ssa-alias.c (revision 272510)
+++ tree-ssa-alias.c (working copy)
@@ -1350,19 +1350,16 @@ nonoverlapping_component_refs_p (const_t
same. */
if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx) == fieldy
|| DECL_BIT_FIELD_REPRESENTATIVE (fieldy) == fieldx)
- {
- ++alias_stats.nonoverlapping_component_refs_p_may_alias;
- return false;
- }
+ ;
/* Different fields of the same record type cannot overlap.
??? Bitfields can overlap at RTL level so punt on them. */
- if (DECL_BIT_FIELD (fieldx) && DECL_BIT_FIELD (fieldy))
+ else if (DECL_BIT_FIELD (fieldx) && DECL_BIT_FIELD (fieldy))
+ ;
+ else
{
- ++alias_stats.nonoverlapping_component_refs_p_may_alias;
- return false;
+ ++alias_stats.nonoverlapping_component_refs_p_no_alias;
+ return true;
}
- ++alias_stats.nonoverlapping_component_refs_p_no_alias;
- return true;
}
}
if (TYPE_UID (typex) < TYPE_UID (typey))
Index: testsuite/gcc.dg/tree-ssa/alias-access-path-6.c
===================================================================
--- testsuite/gcc.dg/tree-ssa/alias-access-path-6.c (nonexistent)
+++ testsuite/gcc.dg/tree-ssa/alias-access-path-6.c (working copy)
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+/* This tests that nonoveralpping_component_refs does not give up
+ on field delcs and continues looking to find mismatch between
+ a1 and a2. */
+struct a {
+ int a:3;
+ int b:3;
+};
+struct b {struct a a1,a2;};
+struct c {struct b b[10];} *cptr;
+struct d {struct c c;} *dptr;
+int
+test(int i,int j)
+{
+ cptr->b[i].a1.a=0;
+ dptr->c.b[j].a2.b=1;
+ return cptr->b[i].a1.a;
+}
+int
+test2(int i,int j)
+{
+ cptr->b[i].a1.a=1;
+ dptr->c.b[j].a1.a=0;
+ return cptr->b[i].a1.a;
+}
+/* { dg-final { scan-tree-dump-times "return 0" 1 "optimized"} } */
+/* { dg-final { scan-tree-dump-not "return 1" "optimized"} } */
