re PR c++/65626 (ICE in fixup_noreturn_call called by tree-ssa-forwprop.c:2492)

2015-03-31  Richard Biener  <rguenther@suse.de>

	PR middle-end/65626
	* tree-cfgcleanup.c (fixup_noreturn_call): Only split the block
	of the noreturn call so it is last and cleanup_control_flow_bb
	can do the CFG part.

	* g++.dg/torture/pr65626.C: New testcase.

From-SVN: r221790

gcc/ChangeLog

+2015-03-31  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/65626
+	* tree-cfgcleanup.c (fixup_noreturn_call): Only split the block
+	of the noreturn call so it is last and cleanup_control_flow_bb
+	can do the CFG part.
+
 2015-03-31  Ilya Enkovich  <ilya.enkovich@intel.com>
 
 	PR target/65531

gcc/testsuite/ChangeLog

+2015-03-31  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/65626
+	* g++.dg/torture/pr65626.C: New testcase.
+
 2015-03-31  Ilya Enkovich  <ilya.enkovich@intel.com>
 
 	PR target/65531

gcc/testsuite/g++.dg/torture/pr65626.C

+// { dg-do compile }
+
+class A {
+      virtual unsigned long m_fn1() const;
+        virtual int &m_fn2(unsigned long) const;
+};
+class C : A {
+public:
+      int &m_fn2(unsigned long) const;
+        unsigned long m_fn1() const;
+};
+class B {
+      void m_fn3(const A &, const int &, const C &, int &) const;
+};
+void B::m_fn3(const A &, const int &, const C &, int &) const {
+      C &a(a);
+        for (long b = 0; a.m_fn1(); b++)
+	      a.m_fn2(0);
+}

gcc/tree-cfgcleanup.c

@@ -579,13 +579,15 @@ remove_forwarder_block (basic_block bb)
   return true;
 }
 
-/* STMT is a call that has been discovered noreturn.  Fixup the CFG
-   and remove LHS.  Return true if something changed.  */
+/* STMT is a call that has been discovered noreturn.  Split the
+   block to prepare fixing up the CFG and remove LHS.
+   Return true if cleanup-cfg needs to run.  */
 
 bool
 fixup_noreturn_call (gimple stmt)
 {
   basic_block bb = gimple_bb (stmt);
+  bool changed = false;
 
   if (gimple_call_builtin_p (stmt, BUILT_IN_RETURN))
     return false;
@@ -604,7 +606,10 @@ fixup_noreturn_call (gimple stmt)
 	    gsi_remove (&gsi, true);
 	}
       else
-	split_block (bb, stmt);
+	{
+	  split_block (bb, stmt);
+	  changed = true;
+	}
     }
 
   /* If there is an LHS, remove it.  */
@@ -626,9 +631,13 @@ fixup_noreturn_call (gimple stmt)
     }
 
   /* Mark the call as altering control flow.  */
-  gimple_call_set_ctrl_altering (stmt, true);
+  if (!gimple_call_ctrl_altering_p (stmt))
+    {
+      gimple_call_set_ctrl_altering (stmt, true);
+      changed = true;
+    }
 
-  return remove_fallthru_edge (bb->succs);
+  return changed;
 }