Add fnspec to C++ new and delete

[Jan Hubicka]

Hi,
this patch makes C++ new and delete operators to be handled as
malloc/free for fnspec.

I still do not understand why free is ".co " and not ".cO ".
I do not think we need to invalidate memory referenced to by blockbeing
freed.

Bootstrapped/regtested x86_64-linux, OK?

Honza

gcc/ChangeLog:

2020-10-27  Jan Hubicka  <hubicka@ucw.cz>

	* gimple.c (gimple_call_fnspec): Handle C++ new and delete.
	* gimple.h (gimple_call_from_new_or_delete): Constify parameter.

gcc/testsuite/ChangeLog:

2020-10-27  Jan Hubicka  <hubicka@ucw.cz>

	* g++.dg/ipa/devirt-24.C: Update template.

diff --git a/gcc/gimple.c b/gcc/gimple.c
index 469e6f369f3..1afed88e1f1 100644
--- a/gcc/gimple.c
+++ b/gcc/gimple.c
@@ -1510,6 +1510,19 @@ gimple_call_fnspec (const gcall *stmt)
     }
   if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
     return builtin_fnspec (gimple_call_fndecl (stmt));
+  tree fndecl = gimple_call_fndecl (stmt);
+  /* If the call is to a replaceable operator delete and results
+     from a delete expression as opposed to a direct call to
+     such operator, then we can treat it as free.  */
+  if (fndecl
+      && DECL_IS_OPERATOR_DELETE_P (fndecl)
+      && gimple_call_from_new_or_delete (stmt))
+    return ".co ";
+  /* Similarly operator new can be treated as malloc.  */
+  if (fndecl
+      && DECL_IS_OPERATOR_NEW_P (fndecl)
+      && gimple_call_from_new_or_delete (stmt))
+    return "mC";
   return "";
 }
 
diff --git a/gcc/gimple.h b/gcc/gimple.h
index 3c9b9965f5a..fdb00d57b07 100644
--- a/gcc/gimple.h
+++ b/gcc/gimple.h
@@ -3405,7 +3405,7 @@ gimple_call_set_from_new_or_delete (gcall *s, bool from_new_or_delete_p)
    from a new or delete expression.  */
 
 static inline bool
-gimple_call_from_new_or_delete (gcall *s)
+gimple_call_from_new_or_delete (const gcall *s)
 {
   return (s->subcode & GF_CALL_FROM_NEW_OR_DELETE) != 0;
 }
diff --git a/gcc/testsuite/g++.dg/ipa/devirt-24.C b/gcc/testsuite/g++.dg/ipa/devirt-24.C
index eaef1f5b3f8..7b5b806dd05 100644
--- a/gcc/testsuite/g++.dg/ipa/devirt-24.C
+++ b/gcc/testsuite/g++.dg/ipa/devirt-24.C
@@ -37,4 +37,4 @@ C *b = new (C);
   }
 }
 /* { dg-final { scan-ipa-dump-times "Discovered a virtual call to a known target" 1 "inline" { xfail *-*-* } } } */
-/* { dg-final { scan-ipa-dump-times "Aggregate passed by reference" 1 "cp"  } } */
+/* { dg-final { scan-ipa-dump-times "Aggregate passed by reference" 2 "cp"  } } */