re PR c++/44127 (G++ emits unnecessary EH code)

	PR c++/44127
gcc:
	* gimple.h (enum gf_mask): Add GF_CALL_NOTHROW.
	(gimple_call_set_nothrow): New.
	* gimple.c (gimple_build_call_from_tree): Call it.
	(gimple_call_flags): Set ECF_NOTHROW from GF_CALL_NOTHROW.
gcc/cp:
	* except.c (dtor_nothrow): Return nonzero for type with
	trivial destructor.

From-SVN: r159408

gcc/ChangeLog

 2010-05-14  Jason Merrill  <jason@redhat.com>
 
 	PR c++/44127
+	* gimple.h (enum gf_mask): Add GF_CALL_NOTHROW.
+	(gimple_call_set_nothrow): New.
+	* gimple.c (gimple_build_call_from_tree): Call it.
+	(gimple_call_flags): Set ECF_NOTHROW from GF_CALL_NOTHROW.
+
+	PR c++/44127
 	* gimplify.c (gimplify_seq_add_stmt): No longer static.
 	* gimple.h: Declare it.
 	* gimple.c (gimple_build_eh_filter): No ops.

gcc/cp/ChangeLog

 2010-05-14  Jason Merrill  <jason@redhat.com>
 
 	PR c++/44127
+	* except.c (dtor_nothrow): Return nonzero for type with
+	trivial destructor.
+
+	PR c++/44127
 	* cp-gimplify.c (gimplify_must_not_throw_expr): Use
 	gimple_build_eh_must_not_throw.
 

gcc/cp/except.c

@@ -214,10 +214,10 @@ do_begin_catch (void)
 static int
 dtor_nothrow (tree type)
 {
-  if (type == NULL_TREE)
+  if (type == NULL_TREE || type == error_mark_node)
     return 0;
 
-  if (!CLASS_TYPE_P (type))
+  if (TYPE_HAS_TRIVIAL_DESTRUCTOR (type))
     return 1;
 
   if (CLASSTYPE_LAZY_DESTRUCTOR (type))

gcc/gimple.c

@@ -297,6 +297,7 @@ gimple_build_call_from_tree (tree t)
   gimple_call_set_return_slot_opt (call, CALL_EXPR_RETURN_SLOT_OPT (t));
   gimple_call_set_from_thunk (call, CALL_FROM_THUNK_P (t));
   gimple_call_set_va_arg_pack (call, CALL_EXPR_VA_ARG_PACK (t));
+  gimple_call_set_nothrow (call, TREE_NOTHROW (t));
   gimple_set_no_warning (call, TREE_NO_WARNING (t));
 
   return call;
@@ -1753,6 +1754,9 @@ gimple_call_flags (const_gimple stmt)
 	flags = 0;
     }
 
+  if (stmt->gsbase.subcode & GF_CALL_NOTHROW)
+    flags |= ECF_NOTHROW;
+
   return flags;
 }
 

gcc/gimple.h

@@ -106,6 +106,7 @@ enum gf_mask {
     GF_CALL_RETURN_SLOT_OPT	= 1 << 2,
     GF_CALL_TAILCALL		= 1 << 3,
     GF_CALL_VA_ARG_PACK		= 1 << 4,
+    GF_CALL_NOTHROW		= 1 << 5,
     GF_OMP_PARALLEL_COMBINED	= 1 << 0,
 
     /* True on an GIMPLE_OMP_RETURN statement if the return does not require
@@ -2213,6 +2214,19 @@ gimple_call_noreturn_p (gimple s)
 }
 
 
+/* If NOTHROW_P is true, GIMPLE_CALL S is a call that is known to not throw
+   even if the called function can throw in other cases.  */
+
+static inline void
+gimple_call_set_nothrow (gimple s, bool nothrow_p)
+{
+  GIMPLE_CHECK (s, GIMPLE_CALL);
+  if (nothrow_p)
+    s->gsbase.subcode |= GF_CALL_NOTHROW;
+  else
+    s->gsbase.subcode &= ~GF_CALL_NOTHROW;
+}
+
 /* Return true if S is a nothrow call.  */
 
 static inline bool

gcc/testsuite/g++.dg/eh/terminate1.C

@@ -7,6 +7,12 @@
 
 // { dg-final { scan-assembler-not "_ZSt9terminatev" } }
 
+// Also there should only be two EH call sites: #0 for throw A() and #1 for
+// _Unwind_Resume.  We don't want call site info for __cxa_end_catch, since
+// ~A is trivial.
+
+// { dg-final { scan-assembler-not "LEHB2" } }
+
 struct A
 {
   A() { }