===================================================================
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+extern int a;
+extern int b;
+extern int c;
+
+int foo(int choose_a)
+{
+ int *p;
+ if (choose_a)
+ p = &a;
+ else
+ p = &b;
+ return p != &c;
+}
+
+int bar ()
+{
+ return &a != &c;
+}
+
+/* We should not optimize away either comparison. */
+/* { dg-final { scan-assembler-times "cmp" 2 } } */
@@ -728,6 +728,12 @@ pp_points_to_solution (pretty_printer *buffer, struct pt_solution *pt)
{
pp_string (buffer, comma);
pp_string (buffer, "restrict");
+ comma = ", ";
+ }
+ if (pt->vars_contains_interposable)
+ {
+ pp_string (buffer, comma);
+ pp_string (buffer, "interposable");
}
pp_string (buffer, ")");
}
@@ -32,12 +32,12 @@ along with GCC; see the file COPYING3. If not see
#include "tree-pretty-print.h"
#include "alias.h"
#include "fold-const.h"
-
#include "langhooks.h"
#include "dumpfile.h"
#include "tree-eh.h"
#include "tree-dfa.h"
#include "ipa-reference.h"
+#include "varasm.h"
/* Broad overview of how alias analysis on gimple works:
@@ -373,14 +373,18 @@ ptrs_compare_unequal (tree ptr1, tree ptr2)
/* We may not use restrict to optimize pointer comparisons.
See PR71062. So we have to assume that restrict-pointed-to
may be in fact obj1. */
- if (!pi || pi->pt.vars_contains_restrict)
+ if (!pi
+ || pi->pt.vars_contains_restrict
+ || pi->pt.vars_contains_interposable)
return false;
if (VAR_P (obj1)
&& (TREE_STATIC (obj1) || DECL_EXTERNAL (obj1)))
{
varpool_node *node = varpool_node::get (obj1);
/* If obj1 may bind to NULL give up (see below). */
- if (! node || ! node->nonzero_address ())
+ if (! node
+ || ! node->nonzero_address ()
+ || ! decl_binds_to_current_def_p (obj1))
return false;
}
return !pt_solution_includes (&pi->pt, obj1);
@@ -553,7 +557,12 @@ dump_points_to_solution (FILE *file, struct pt_solution *pt)
comma = ", ";
}
if (pt->vars_contains_restrict)
- fprintf (file, "%srestrict", comma);
+ {
+ fprintf (file, "%srestrict", comma);
+ comma = ", ";
+ }
+ if (pt->vars_contains_interposable)
+ fprintf (file, "%sinterposable", comma);
fprintf (file, ")");
}
}
@@ -57,6 +57,8 @@ struct GTY(()) pt_solution
/* Nonzero if the vars bitmap includes a anonymous variable used to
represent storage pointed to by a restrict qualified pointer. */
unsigned int vars_contains_restrict : 1;
+ /* Nonzero if the vars bitmap includes an interposable variable. */
+ unsigned int vars_contains_interposable : 1;
/* Set of variables that this pointer may point to. */
bitmap vars;
@@ -39,6 +39,8 @@
#include "tree-dfa.h"
#include "params.h"
#include "gimple-walk.h"
+#include "varasm.h"
+
/* The idea behind this analyzer is to generate set constraints from the
program, then solve the resulting constraints in order to generate the
@@ -6360,6 +6362,13 @@ set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt,
&& fndecl
&& ! auto_var_in_fn_p (vi->decl, fndecl)))
pt->vars_contains_nonlocal = true;
+
+ /* If we have a variable that is interposable record that fact
+ for pointer comparison simplification. */
+ if (VAR_P (vi->decl)
+ && (TREE_STATIC (vi->decl) || DECL_EXTERNAL (vi->decl))
+ && ! decl_binds_to_current_def_p (vi->decl))
+ pt->vars_contains_interposable = true;
}
else if (TREE_CODE (vi->decl) == FUNCTION_DECL
@@ -7592,7 +7601,8 @@ make_pass_build_ealias (gcc::context *ctxt)
/* IPA PTA solutions for ESCAPED. */
struct pt_solution ipa_escaped_pt
- = { true, false, false, false, false, false, false, false, false, NULL };
+ = { true, false, false, false, false,
+ false, false, false, false, false, NULL };
/* Associate node with varinfo DATA. Worker for
cgraph_for_symbol_thunks_and_aliases. */