re PR c++/60750 (double free after std::move on string inside throw when…

re PR c++/60750 (double free after std::move on string inside throw when compiled with optimization)

2014-04-07  Richard Biener  <rguenther@suse.de>

	PR middle-end/60750
	* tree-ssa-operands.c (maybe_add_call_vops): Also add VDEFs
	for noreturn calls.
	* tree-cfgcleanup.c (fixup_noreturn_call): Do not remove VDEFs.

	* g++.dg/torture/pr60750.C: New testcase.
	* gcc.dg/tree-ssa/20040517-1.c: Adjust.

From-SVN: r209179

gcc/ChangeLog

+2014-04-07  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/60750
+	* tree-ssa-operands.c (maybe_add_call_vops): Also add VDEFs
+	for noreturn calls.
+	* tree-cfgcleanup.c (fixup_noreturn_call): Do not remove VDEFs.
+
 2014-04-06  John David Anglin  <danglin@gcc.gnu.org>
 
 	PR debug/55794

gcc/testsuite/ChangeLog

+2014-04-07  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/60750
+	* g++.dg/torture/pr60750.C: New testcase.
+	* gcc.dg/tree-ssa/20040517-1.c: Adjust.
+
 2014-04-06  Andreas Schwab  <schwab@linux-m68k.org>
 
 	* gcc.c-torture/compile/pr60655-1.c: Use __SIZE_TYPE__ for size_t.

gcc/testsuite/g++.dg/torture/pr60750.C

+// { dg-do run }
+// { dg-options "-std=c++11" }
+
+#include <string>
+#include <stdexcept>
+
+const std::string err_prefix = "Problem: ";
+void thrower (std::string msg)
+{
+  throw std::runtime_error(err_prefix + std::move(msg));
+}
+
+int main(int argc, char **argv)
+{
+  try {
+      std::string base = "hello";
+      thrower(std::move(base));
+  } catch (const std::runtime_error &e) {
+  }
+  return 0;
+}

gcc/testsuite/gcc.dg/tree-ssa/20040517-1.c

@@ -16,6 +16,7 @@ void bar (void)
 /* We used to treat malloc functions like pure and const functions, but
    malloc functions may clobber global memory.  Only the function result
    does not alias any other pointer.
-   Hence, we must have a VDEF for a before and after the call to foo().  */
-/* { dg-final { scan-tree-dump-times "VDEF" 2 "alias"} } */
+   Hence, we must have a VDEF for a before and after the call to foo().
+   And one after the call to abort().  */
+/* { dg-final { scan-tree-dump-times "VDEF" 3 "alias"} } */
 /* { dg-final { cleanup-tree-dump "alias" } } */

gcc/tree-cfgcleanup.c

@@ -586,9 +586,6 @@ fixup_noreturn_call (gimple stmt)
       update_stmt (stmt);
       changed = true;
     }
-  /* Similarly remove VDEF if there is any.  */
-  else if (gimple_vdef (stmt))
-    update_stmt (stmt);
   return changed;
 }
 

gcc/tree-ssa-operands.c

@@ -648,10 +648,8 @@ maybe_add_call_vops (struct function *fn, gimple stmt)
      call-clobbered.  */
   if (!(call_flags & ECF_NOVOPS))
     {
-      /* A 'pure' or a 'const' function never call-clobbers anything.
-	 A 'noreturn' function might, but since we don't return anyway
-	 there is no point in recording that.  */
-      if (!(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
+      /* A 'pure' or a 'const' function never call-clobbers anything.  */
+      if (!(call_flags & (ECF_PURE | ECF_CONST)))
 	add_virtual_operand (fn, stmt, opf_def);
       else if (!(call_flags & ECF_CONST))
 	add_virtual_operand (fn, stmt, opf_use);