PR lto/69866

	* lto-symtab.c (lto_symtab_merge_symbols): Drop useless definitions
	that resolved externally.

	* gcc.dg/lto/pr69866_0.c: New test.
	* gcc.dg/lto/pr69866_1.c: Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@249224 138bc75d-0d04-0410-961f-82ee72b054a4

6 files changed, 69 insertions, 1 deletions

diff --git a/gcc/lto/ChangeLog b/gcc/lto/ChangeLog
index e63f2037191..58601c54b46 100644
--- a/gcc/lto/ChangeLog
+++ b/gcc/lto/ChangeLog
@@ -1,3 +1,10 @@
+2017-06-15  Jan Hubicka  <hubicka@ucw.cz>
+	    Thomas Preud'homme  <thomas.preudhomme@arm.com>
+
+	PR lto/69866
+	* lto-symtab.c (lto_symtab_merge_symbols): Drop useless definitions
+	that resolved externally.
+
 2017-05-23  Jan Hubicka  <hubicka@ucw.cz>
 
 	* lto.c (do_whole_program_analysis): Replace inline_free_summary
diff --git a/gcc/lto/lto-partition.c b/gcc/lto/lto-partition.c
index 3600ab23bd9..620deac090b 100644
--- a/gcc/lto/lto-partition.c
+++ b/gcc/lto/lto-partition.c
@@ -132,7 +132,7 @@ add_symbol_to_partition_1 (ltrans_partition part, symtab_node *node)
 
   /* Be sure that we never try to duplicate partitioned symbol
      or add external symbol.  */
-  gcc_assert (c != SYMBOL_EXTERNAL
+  gcc_assert ((c != SYMBOL_EXTERNAL || node->alias)
 	      && (c == SYMBOL_DUPLICATE || !symbol_partitioned_p (node)));
 
   part->symbols++;
diff --git a/gcc/lto/lto-symtab.c b/gcc/lto/lto-symtab.c
index 9fd94861c6d..019677eaf95 100644
--- a/gcc/lto/lto-symtab.c
+++ b/gcc/lto/lto-symtab.c
@@ -952,6 +952,42 @@ lto_symtab_merge_symbols (void)
 	      if (tgt)
 		node->resolve_alias (tgt, true);
 	    }
+	  /* If the symbol was preempted outside IR, see if we want to get rid
+	     of the definition.  */
+	  if (node->analyzed
+	      && !DECL_EXTERNAL (node->decl)
+	      && (node->resolution == LDPR_PREEMPTED_REG
+		  || node->resolution == LDPR_RESOLVED_IR
+		  || node->resolution == LDPR_RESOLVED_EXEC
+		  || node->resolution == LDPR_RESOLVED_DYN))
+	    {
+	      DECL_EXTERNAL (node->decl) = 1;
+	      /* If alias to local symbol was preempted by external definition,
+		 we know it is not pointing to the local symbol.  Remove it.  */
+	      if (node->alias
+		  && !node->weakref
+		  && !node->transparent_alias
+		  && node->get_alias_target ()->binds_to_current_def_p ())
+		{
+		  node->alias = false;
+		  node->remove_all_references ();
+		  node->definition = false;
+		  node->analyzed = false;
+		  node->cpp_implicit_alias = false;
+		}
+	      else if (!node->alias
+		       && node->definition
+		       && node->get_availability () <= AVAIL_INTERPOSABLE)
+		{
+		  if ((cnode = dyn_cast <cgraph_node *> (node)) != NULL)
+		    cnode->reset ();
+		  else
+		    {
+		      node->analyzed = node->definition = false;
+		      node->remove_all_references ();
+		    }
+		}
+	    }
 
 	  if (!(cnode = dyn_cast <cgraph_node *> (node))
 	      || !cnode->clone_of
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 3677d15c453..a79f533992e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2017-06-15  Thomas Preud'homme  <thomas.preudhomme@arm.com>
+
+	PR lto/69866
+	* gcc.dg/lto/pr69866_0.c: New test.
+	* gcc.dg/lto/pr69866_1.c: Likewise.
+
 2017-06-15  Jozef Lawrynowicz	<jozef.l@somniumtech.com>
 
 	PR target/78818
diff --git a/gcc/testsuite/gcc.dg/lto/pr69866_0.c b/gcc/testsuite/gcc.dg/lto/pr69866_0.c
new file mode 100644
index 00000000000..f49ef8d4c1d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr69866_0.c
@@ -0,0 +1,13 @@
+/* { dg-lto-do link } */
+
+int _umh(int i)
+{
+  return i+1;
+}
+
+int weaks(int i) __attribute__((weak, alias("_umh")));
+
+int main()
+{
+  return weaks(10);
+}
diff --git a/gcc/testsuite/gcc.dg/lto/pr69866_1.c b/gcc/testsuite/gcc.dg/lto/pr69866_1.c
new file mode 100644
index 00000000000..3a14f850eef
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr69866_1.c
@@ -0,0 +1,6 @@
+/* { dg-options { -fno-lto } } */
+
+int weaks(int i)
+{
+  return i+1;
+}