C++ PATCH for c++/59231 (missed warning in template instantiation)

commit 04b9e92db4acaa442552e87b18682c7b01275017
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Feb 26 13:49:23 2014 -0500

    	PR c++/59231
    	PR c++/11586
    	PR c++/14710
    	PR c++/57132
    gcc/
    	* c-common.c (shorten_compare): Don't check
    	c_inhibit_evaluation_warnings.
    gcc/cp/
    	* pt.c (struct warning_sentinel): New.
    	(tsubst_copy_and_build): Use it instead of
    	c_inhibit_evaluation_warnings.

diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index e23a9df..abd96fb 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -4218,8 +4218,7 @@  shorten_compare (location_t loc, tree *op0_ptr, tree *op1_ptr,
 	  type = c_common_unsigned_type (type);
 	}
 
-      if (TREE_CODE (primop0) != INTEGER_CST
-	  && c_inhibit_evaluation_warnings == 0)
+      if (TREE_CODE (primop0) != INTEGER_CST)
 	{
 	  if (val == truthvalue_false_node)
 	    warning_at (loc, OPT_Wtype_limits,
@@ -4299,7 +4298,6 @@  shorten_compare (location_t loc, tree *op0_ptr, tree *op1_ptr,
 	     warning.  */
 	  bool warn = 
 	    warn_type_limits && !in_system_header_at (loc)
-	    && c_inhibit_evaluation_warnings == 0
 	    && !(TREE_CODE (primop0) == INTEGER_CST
 		 && !TREE_OVERFLOW (convert (c_common_signed_type (type),
 					     primop0)))
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 1f5a2b7..8126905 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -1,4 +1,4 @@ 
-/* Handle parameterized types (templates) for GNU C++.
+/* Handle parameterized types (templates) for GNU -*- C++ -*-.
    Copyright (C) 1992-2014 Free Software Foundation, Inc.
    Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
    Rewritten by Jason Merrill (jason@cygnus.com).
@@ -14063,6 +14063,16 @@  tsubst_non_call_postfix_expression (tree t, tree args,
   return t;
 }
 
+/* Sentinel to disable certain warnings during template substitution.  */
+
+struct warning_sentinel {
+  int &flag;
+  int val;
+  warning_sentinel(int& flag, bool suppress=true)
+    : flag(flag), val(flag) { if (suppress) flag = 0; }
+  ~warning_sentinel() { flag = val; }
+};
+
 /* Like tsubst but deals with expressions and performs semantic
    analysis.  FUNCTION_P is true if T is the "F" in "F (ARGS)".  */
 
@@ -14229,7 +14239,7 @@  tsubst_copy_and_build (tree t,
 
 	op = RECUR (TREE_OPERAND (t, 0));
 
-	++c_inhibit_evaluation_warnings;
+	warning_sentinel s(warn_useless_cast);
 	switch (TREE_CODE (t))
 	  {
 	  case CAST_EXPR:
@@ -14250,7 +14260,6 @@  tsubst_copy_and_build (tree t,
 	  default:
 	    gcc_unreachable ();
 	  }
-	--c_inhibit_evaluation_warnings;
 
 	RETURN (r);
       }
@@ -14325,11 +14334,9 @@  tsubst_copy_and_build (tree t,
     case MEMBER_REF:
     case DOTSTAR_EXPR:
       {
-	tree r;
-
-	++c_inhibit_evaluation_warnings;
-
-	r = build_x_binary_op
+	warning_sentinel s1(warn_type_limits);
+	warning_sentinel s2(warn_div_by_zero);
+	tree r = build_x_binary_op
 	  (input_location, TREE_CODE (t),
 	   RECUR (TREE_OPERAND (t, 0)),
 	   (TREE_NO_WARNING (TREE_OPERAND (t, 0))
@@ -14344,8 +14351,6 @@  tsubst_copy_and_build (tree t,
 	if (EXPR_P (r) && TREE_NO_WARNING (t))
 	  TREE_NO_WARNING (r) = TREE_NO_WARNING (t);
 
-	--c_inhibit_evaluation_warnings;
-
 	RETURN (r);
       }
 
@@ -14460,11 +14465,8 @@  tsubst_copy_and_build (tree t,
 
     case MODOP_EXPR:
       {
-	tree r;
-
-	++c_inhibit_evaluation_warnings;
-
-	r = build_x_modify_expr
+	warning_sentinel s(warn_div_by_zero);
+	tree r = build_x_modify_expr
 	  (EXPR_LOCATION (t),
 	   RECUR (TREE_OPERAND (t, 0)),
 	   TREE_CODE (TREE_OPERAND (t, 1)),
@@ -14479,8 +14481,6 @@  tsubst_copy_and_build (tree t,
 	if (TREE_NO_WARNING (t))
 	  TREE_NO_WARNING (r) = TREE_NO_WARNING (t);
 
-	--c_inhibit_evaluation_warnings;
-
 	RETURN (r);
       }
 
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 5fc0e6b..1e14b63 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -6282,8 +6282,7 @@  void
 maybe_warn_about_useless_cast (tree type, tree expr, tsubst_flags_t complain)
 {
   if (warn_useless_cast
-      && complain & tf_warning
-      && c_inhibit_evaluation_warnings == 0)
+      && complain & tf_warning)
     {
       if (REFERENCE_REF_P (expr))
 	expr = TREE_OPERAND (expr, 0);
diff --git a/gcc/testsuite/g++.dg/cilk-plus/AN/array_test2_tplt.cc b/gcc/testsuite/g++.dg/cilk-plus/AN/array_test2_tplt.cc
index 87c37e1..041c052 100644
--- a/gcc/testsuite/g++.dg/cilk-plus/AN/array_test2_tplt.cc
+++ b/gcc/testsuite/g++.dg/cilk-plus/AN/array_test2_tplt.cc
@@ -1,5 +1,5 @@ 
 /* { dg-do run } */
-/* { dg-options "-fcilkplus" } */
+/* { dg-options "-fcilkplus -Wno-overflow" } */
 
 #include <cstdlib>
 #include <string.h>
diff --git a/gcc/testsuite/g++.dg/cpp0x/overflow1.C b/gcc/testsuite/g++.dg/cpp0x/overflow1.C
index 7033e9c..b8591b4 100644
--- a/gcc/testsuite/g++.dg/cpp0x/overflow1.C
+++ b/gcc/testsuite/g++.dg/cpp0x/overflow1.C
@@ -1,3 +1,5 @@ 
+// { dg-prune-output "-Woverflow" }
+
 template <long long i>
 struct Fib
 {
diff --git a/gcc/testsuite/g++.dg/warn/Wsign-compare-7.C b/gcc/testsuite/g++.dg/warn/Wsign-compare-7.C
new file mode 100644
index 0000000..51f13f6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wsign-compare-7.C
@@ -0,0 +1,18 @@ 
+// PR c++/59231
+// { dg-options "-Wsign-compare" }
+
+template<class X, class Y>
+bool equals(X x, Y y)
+{
+    return (x == y);		// { dg-warning "signed" }
+}
+
+int main()
+{
+  unsigned long x = 2;
+  signed int y = 2;
+
+  if(!equals (x, y))
+    return 1;
+  return 0;
+}