ICF: properly handle LABEL_DECLs (PR tree-opt/81696).

2017-08-08  Martin Liska  <mliska@suse.cz>

	PR tree-opt/81696
	* ipa-icf-gimple.c (func_checker::compare_cst_or_decl): Consider
	LABEL_DECLs that can be from a different function.
2017-08-08  Martin Liska  <mliska@suse.cz>

	PR tree-opt/81696
	* gcc.dg/ipa/pr81696.c: New test.

From-SVN: r250951

gcc/ChangeLog

+2017-08-08  Martin Liska  <mliska@suse.cz>
+
+	PR tree-opt/81696
+	* ipa-icf-gimple.c (func_checker::compare_cst_or_decl): Consider
+	LABEL_DECLs that can be from a different function.
+
 2017-08-08  Bin Cheng  <bin.cheng@arm.com>
 
 	PR tree-optimization/81744

gcc/ipa-icf-gimple.c

@@ -361,10 +361,14 @@ func_checker::compare_cst_or_decl (tree t1, tree t2)
       }
     case LABEL_DECL:
       {
+	if (t1 == t2)
+	  return true;
+
 	int *bb1 = m_label_bb_map.get (t1);
 	int *bb2 = m_label_bb_map.get (t2);
 
-	return return_with_debug (*bb1 == *bb2);
+	/* Labels can point to another function (non-local GOTOs).  */
+	return return_with_debug (bb1 != NULL && bb2 != NULL && *bb1 == *bb2);
       }
     case PARM_DECL:
     case RESULT_DECL:

gcc/testsuite/ChangeLog

+2017-08-08  Martin Liska  <mliska@suse.cz>
+
+	PR tree-opt/81696
+	* gcc.dg/ipa/pr81696.c: New test.
+
 2017-08-08  Bin Cheng  <bin.cheng@arm.com>
 
 	PR tree-optimization/81744

gcc/testsuite/gcc.dg/ipa/pr81696.c

+/* { dg-options "-O2 -fdump-ipa-icf-details"  } */
+
+int
+main (int argc, char **argv)
+{
+  __label__ lab4, lab5, lab6;
+
+  void foo (void) { goto lab4; }
+  void foo2 (void) { goto lab4; }
+  void bar (void) { goto lab5; }
+  void baz (void) { goto lab6; }
+
+  if (argc)
+    foo ();
+  else
+    foo2 ();
+
+ lab4:;
+  bar ();
+ lab5:;
+  baz ();
+ lab6:;
+  return 0;
+}
+
+/* { dg-final { scan-ipa-dump "Equal symbols: 1" "icf"  } } */