re PR c++/57132 (spurious warning: division by zero [-Wdiv-by-zero] in if (m) res...

/cp
2013-05-01  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/57132
	* pt.c (tsubst_copy_and_build, MODOP_EXPR): Increase / decrease
	c_inhibit_evaluation_warnings around build_x_modify_expr call.

/testsuite
2013-05-01  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/57132
	* g++.dg/warn/Wdiv-by-zero-bogus-2.C: New.

From-SVN: r198504

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 09f10df31828be350abb51c077d013ed3af17bf6..e4996fb0492ab4cbfff8d627cf3d4f6edb69c619 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2013-05-01  Paolo Carlini  <paolo.carlini@oracle.com>
+
+       PR c++/57132
+       * pt.c (tsubst_copy_and_build, MODOP_EXPR): Increase / decrease
+       c_inhibit_evaluation_warnings around build_x_modify_expr call.
+
 2013-05-01  Paolo Carlini  <paolo.carlini@oracle.com>
 
        PR c++/57092

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 57f65b3be0e4dd36d463207ec55498aa47bb738e..33ab292b9b542da47cbdde141b38aff43c83dfa0 100644 (file)
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -13810,7 +13810,11 @@ tsubst_copy_and_build (tree t,
 
     case MODOP_EXPR:
       {
-       tree r = build_x_modify_expr
+       tree r;
+
+       ++c_inhibit_evaluation_warnings;
+
+       r = build_x_modify_expr
          (EXPR_LOCATION (t),
           RECUR (TREE_OPERAND (t, 0)),
           TREE_CODE (TREE_OPERAND (t, 1)),
@@ -13824,6 +13828,9 @@ tsubst_copy_and_build (tree t,
           here.  */
        if (TREE_NO_WARNING (t))
          TREE_NO_WARNING (r) = TREE_NO_WARNING (t);
+
+       --c_inhibit_evaluation_warnings;
+
        RETURN (r);
       }
 

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 939d4596b6d760c53fe6a87ea5ed362f8de7ae8e..bce4185ca693ed44b10d22cc4c50ee9f45ed1ade 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2013-05-01  Paolo Carlini  <paolo.carlini@oracle.com>
+
+       PR c++/57132
+       * g++.dg/warn/Wdiv-by-zero-bogus-2.C: New.
+
 2013-05-01  Vladimir Makarov  <vmakarov@redhat.com>
 
        PR target/57091

diff --git a/gcc/testsuite/g++.dg/warn/Wdiv-by-zero-bogus-2.C b/gcc/testsuite/g++.dg/warn/Wdiv-by-zero-bogus-2.C
new file mode 100644 (file)
index 0000000..b7556ea
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wdiv-by-zero-bogus-2.C
@@ -0,0 +1,18 @@
+// PR c++/57132
+
+template<unsigned m, unsigned a>
+struct mod 
+{
+  static unsigned calc(unsigned x) {
+    unsigned res = a * x;
+    if (m)
+      res %= m;
+    return res;
+  }
+};
+
+int main()
+{
+  mod<3,2>::calc(7);
+  mod<0,2>::calc(7);
+}