Hi,
while analyzing the previous bug I noticed that nothrow propagation handles
visibility wrong wrt aliases. This patch fixes it and also makes the code a bit
more effective.
Bootstrapped/regtested x86_64-linux, comitted.
Honza
* ipa-pure-const.c (ignore_edge): Rename to ...
(ignore_edge_for_nothrow) ... this one; also ignore eges to
interposable functions or ones that can not throw.
(propagate_nothrow): Fix handling of availability.
Index: ipa-pure-const.c
===================================================================
--- ipa-pure-const.c (revision 231216)
+++ ipa-pure-const.c (working copy)
@@ -1124,11 +1124,18 @@ pure_const_read_summary (void)
}
}
+/* We only propagate across edges that can throw externally and their callee
+ is not interposable. */
static bool
-ignore_edge (struct cgraph_edge *e)
+ignore_edge_for_nothrow (struct cgraph_edge *e)
{
- return (!e->can_throw_external);
+ if (!e->can_throw_external || TREE_NOTHROW (e->callee->decl))
+ return true;
+
+ enum availability avail;
+ cgraph_node *n = e->callee->function_or_virtual_thunk_symbol (&avail);
+ return (avail <= AVAIL_INTERPOSABLE || TREE_NOTHROW (n->decl));
}
/* Return true if NODE is self recursive function.
@@ -1491,7 +1498,8 @@ propagate_nothrow (void)
int i;
struct ipa_dfs_info * w_info;
- order_pos = ipa_reduced_postorder (order, true, false, ignore_edge);
+ order_pos = ipa_reduced_postorder (order, true, false,
+ ignore_edge_for_nothrow);
if (dump_file)
{
cgraph_node::dump_cgraph (dump_file);
@@ -1515,32 +1523,38 @@ propagate_nothrow (void)
while (w && !can_throw)
{
struct cgraph_edge *e, *ie;
- funct_state w_l = get_function_state (w);
-
- if (w_l->can_throw
- || w->get_availability () == AVAIL_INTERPOSABLE)
- can_throw = true;
- for (e = w->callees; e && !can_throw; e = e->next_callee)
+ if (!TREE_NOTHROW (w->decl))
{
- enum availability avail;
- struct cgraph_node *y = e->callee->
- function_or_virtual_thunk_symbol (&avail);
+ funct_state w_l = get_function_state (w);
- if (avail > AVAIL_INTERPOSABLE)
+ if (w_l->can_throw
+ || w->get_availability () == AVAIL_INTERPOSABLE)
+ can_throw = true;
+
+ for (e = w->callees; e && !can_throw; e = e->next_callee)
{
- funct_state y_l = get_function_state (y);
+ enum availability avail;
+
+ if (!e->can_throw_external || TREE_NOTHROW (e->callee->decl))
+ continue;
+
+ struct cgraph_node *y = e->callee->
+ function_or_virtual_thunk_symbol (&avail);
- if (y_l->can_throw && !TREE_NOTHROW (w->decl)
- && e->can_throw_external)
+ /* We can use info about the callee only if we know it can
+ not be interposed. */
+ if (avail <= AVAIL_INTERPOSABLE
+ || (!TREE_NOTHROW (y->decl)
+ && get_function_state (y)->can_throw))
can_throw = true;
}
- else if (e->can_throw_external && !TREE_NOTHROW (y->decl))
- can_throw = true;
+ for (ie = w->indirect_calls; ie && !can_throw;
+ ie = ie->next_callee)
+ if (ie->can_throw_external
+ && !(ie->indirect_info->ecf_flags & ECF_NOTHROW))
+ can_throw = true;
}
- for (ie = w->indirect_calls; ie && !can_throw; ie = ie->next_callee)
- if (ie->can_throw_external)
- can_throw = true;
w_info = (struct ipa_dfs_info *) w->aux;
w = w_info->next_cycle;
}
@@ -1650,7 +1664,7 @@ skip_function_for_local_pure_const (stru
if (node->get_availability () <= AVAIL_INTERPOSABLE)
{
if (dump_file)
- fprintf (dump_file, "Function is not available or overwritable; not
analyzing.\n");
+ fprintf (dump_file, "Function is not available or interposable; not
analyzing.\n");
return true;
}
return false;
