> I don't understand why we need this (testcase?) because get_alias_set ()
> is supposed to do the alias-set of pointer globbing for us.
Hi,
After some experimentation I managed to derive self contained testcase (other
than GCC itself).
struct a/b/c gets the same TYPE_CANONICAL which is different from struct b.
Without that
change in recording component aliases then the alias_set of struct b has
component float *
instead of int *. Eventually in main we optimize out the store to int * because
we do not
see the conflict.
One needs to add the extra garbage around to be sure that things are streamed
in proper order and also in proper order shipped to ltrans and finally the
gimple optimizers are not smart enough to get the propagation without TBAA
oracle help.
Comitted.
* gcc.c-torture/execute/lto-tbaa-1.c: New testcase.
Index: gcc.c-torture/execute/lto-tbaa-1.c
===================================================================
--- gcc.c-torture/execute/lto-tbaa-1.c (revision 0)
+++ gcc.c-torture/execute/lto-tbaa-1.c (revision 0)
@@ -0,0 +1,42 @@
+/* { dg-additional-options "-fno-early-inlining -fno-ipa-cp" } */
+struct a {
+ float *b;
+} *a;
+struct b {
+ int *b;
+} b;
+struct c {
+ float *b;
+} *c;
+int d;
+use_a (struct a *a)
+{
+}
+set_b (int **a)
+{
+ *a=&d;
+}
+use_c (struct c *a)
+{
+}
+__attribute__ ((noinline)) int **retme(int **val)
+{
+ return val;
+}
+int e;
+struct b b= {&e};
+struct b b2;
+struct b b3;
+int **ptr = &b2.b;
+main ()
+{
+ a= (void *)0;
+ b.b=&e;
+ ptr =retme ( &b.b);
+ set_b (ptr);
+ b3=b;
+ if (b3.b != &d)
+ __builtin_abort ();
+ c= (void *)0;
+ return 0;
+}
