alias.c: Include ipa-utils.h.

	* alias.c: Include ipa-utils.h.
	(get_alias_set): Try to complete ODR type via ODR type hash lookup.
	* ipa-devirt.c (prevailing_odr_type): New.
	* ipa-utils.h (previaling_odr_type): Declare.

	* g++.dg/lto/alias-1_0.C: New testcase.
	* g++.dg/lto/alias-1_1.C: New testcase.

From-SVN: r271837

7 files changed, 83 insertions, 0 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a1e8127..491577b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2019-05-31  Jan Hubicka  <jh@suse.cz>
+
+	* alias.c: Include ipa-utils.h.
+	(get_alias_set): Try to complete ODR type via ODR type hash lookup.
+	* ipa-devirt.c (prevailing_odr_type): New.
+	* ipa-utils.h (previaling_odr_type): Declare.
+
 2019-05-31  H.J. Lu  <hongjiu.lu@intel.com>
 	    Hongtao Liu  <hongtao.liu@intel.com>
 
diff --git a/gcc/alias.c b/gcc/alias.c
index d3cc07c..eece84a 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -39,6 +39,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "cfganal.h"
 #include "rtl-iter.h"
 #include "cgraph.h"
+#include "ipa-utils.h"
 
 /* The aliasing API provided here solves related but different problems:
 
@@ -1008,6 +1009,14 @@ get_alias_set (tree t)
 	}
       p = TYPE_MAIN_VARIANT (p);
 
+      /* In LTO for C++ programs we can turn in complete types to complete
+	 using ODR name lookup.  */
+      if (in_lto_p && TYPE_STRUCTURAL_EQUALITY_P (p) && odr_type_p (p))
+	{
+	  p = prevailing_odr_type (p);
+	  gcc_checking_assert (TYPE_MAIN_VARIANT (p) == p);
+	}
+
       /* Make void * compatible with char * and also void **.
 	 Programs are commonly violating TBAA by this.
 
diff --git a/gcc/ipa-devirt.c b/gcc/ipa-devirt.c
index a51b151..e9cb180 100644
--- a/gcc/ipa-devirt.c
+++ b/gcc/ipa-devirt.c
@@ -2170,6 +2170,20 @@ get_odr_type (tree type, bool insert)
   return val;
 }
 
+/* Return type that in ODR type hash prevailed TYPE.  Be careful and punt
+   on ODR violations.  */
+
+tree
+prevailing_odr_type (tree type)
+{
+  odr_type t = get_odr_type (type, false);
+  if (!t || t->odr_violated)
+    return type;
+  return t->type;
+}
+
+/* Return true if we reported some ODR violation on TYPE.  */
+
 bool
 odr_type_violation_reported_p (tree type)
 {
diff --git a/gcc/ipa-utils.h b/gcc/ipa-utils.h
index b70e8c5..77cf3d3d 100644
--- a/gcc/ipa-utils.h
+++ b/gcc/ipa-utils.h
@@ -92,6 +92,7 @@ void warn_types_mismatch (tree t1, tree t2, location_t loc1 = UNKNOWN_LOCATION,
 bool odr_or_derived_type_p (const_tree t);
 bool odr_types_equivalent_p (tree type1, tree type2);
 bool odr_type_violation_reported_p (tree type);
+tree prevailing_odr_type (tree type);
 
 /* Return vector containing possible targets of polymorphic call E.
    If COMPLETEP is non-NULL, store true if the list is complete. 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 04fb8bc..0663f4c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-05-31  Jan Hubicka  <jh@suse.cz>
+
+	* g++.dg/lto/alias-1_0.C: New testcase.
+	* g++.dg/lto/alias-1_1.C: New testcase.
+
 2019-05-31  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/89355
diff --git a/gcc/testsuite/g++.dg/lto/alias-1_0.C b/gcc/testsuite/g++.dg/lto/alias-1_0.C
new file mode 100644
index 0000000..32f3ff0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lto/alias-1_0.C
@@ -0,0 +1,31 @@
+/* { dg-lto-do run } */
+/* { dg-lto-options { { -O2 -flto } } } */
+
+/* With LTO we consider all pointers to incomplete types to be possibly
+   aliasing.  This makes *bptr to alias with aptr.
+   However with C++ ODR rule we can turn incomplete pointers to complete
+   dragging in info from alias-1_1.C.  */
+
+#include <string.h>
+
+typedef int (*fnptr) ();
+
+__attribute__ ((used))
+struct a *aptr;
+
+__attribute__ ((used))
+struct b **bptr = (struct b**)&aptr;
+extern void init ();
+extern void inline_me_late (int);
+
+
+int
+main (int argc, char **argv)
+{
+  init ();
+  aptr = 0;
+  inline_me_late (argc);
+  if (!__builtin_constant_p (aptr == 0))
+    __builtin_abort ();
+  return (size_t)aptr;
+}
diff --git a/gcc/testsuite/g++.dg/lto/alias-1_1.C b/gcc/testsuite/g++.dg/lto/alias-1_1.C
new file mode 100644
index 0000000..49e8217
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lto/alias-1_1.C
@@ -0,0 +1,16 @@
+#include <string.h>
+struct a {int a;} a;
+struct b {short b;} b;
+extern struct b **bptr;
+void
+inline_me_late (int argc)
+{
+  if (argc == -1)
+    *bptr = (struct b *)(size_t)1;
+}
+void
+init()
+{
+  a.a=1;
+  b.b=2;
+}