re PR c++/56607 (GCC fails to warn on division by zero)

	PR c++/56607
	* typeck.c (cp_build_binary_op): When calling warn_for_div_by_zero,
	pass op1 through maybe_constant_value first.

	* g++.dg/warn/Wdiv-by-zero-2.C: New test.
	* c-c++-common/pr56607.c: New test.

From-SVN: r196704

5 files changed, 77 insertions, 2 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 3f05f29..dc61d9b 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2013-03-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/56607
+	* typeck.c (cp_build_binary_op): When calling warn_for_div_by_zero,
+	pass op1 through maybe_constant_value first.
+
 2013-03-16  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/56582
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 58ebcc0..96e0ad8 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -4015,7 +4015,7 @@ cp_build_binary_op (location_t location,
 	{
 	  enum tree_code tcode0 = code0, tcode1 = code1;
 
-	  warn_for_div_by_zero (location, op1);
+	  warn_for_div_by_zero (location, maybe_constant_value (op1));
 
 	  if (tcode0 == COMPLEX_TYPE || tcode0 == VECTOR_TYPE)
 	    tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
@@ -4051,7 +4051,7 @@ cp_build_binary_op (location_t location,
 
     case TRUNC_MOD_EXPR:
     case FLOOR_MOD_EXPR:
-      warn_for_div_by_zero (location, op1);
+      warn_for_div_by_zero (location, maybe_constant_value (op1));
 
       if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
 	  && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f9fb7f6..db0f92e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2013-03-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/56607
+	* g++.dg/warn/Wdiv-by-zero-2.C: New test.
+	* c-c++-common/pr56607.c: New test.
+
 2013-03-16  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/56582
diff --git a/gcc/testsuite/c-c++-common/pr56607.c b/gcc/testsuite/c-c++-common/pr56607.c
new file mode 100644
index 0000000..d7faa81
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr56607.c
@@ -0,0 +1,29 @@
+/* PR c++/56607 */
+/* { dg-do compile { target { { lp64 || ilp32 } || llp64 } } } */
+/* { dg-options "-O2 -Wdiv-by-zero" } */
+
+int
+f1 (void)
+{
+  return 1 / (sizeof (char) - 1);	/* { dg-warning "division by zero" } */
+}
+
+int
+f2 (void)
+{
+  const int x = sizeof (char) - 1;
+  return 1 / x;				/* { dg-warning "division by zero" "" { target c++ } } */
+}
+
+int
+f3 (void)
+{
+  return 1 / (sizeof (int) / 3 - 1);	/* { dg-warning "division by zero" } */
+}
+
+int
+f4 (void)
+{
+  const int x = sizeof (int) / 3 - 1;
+  return 1 / x;				/* { dg-warning "division by zero" "" { target c++ } } */
+}
diff --git a/gcc/testsuite/g++.dg/warn/Wdiv-by-zero-2.C b/gcc/testsuite/g++.dg/warn/Wdiv-by-zero-2.C
new file mode 100644
index 0000000..d7e226c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wdiv-by-zero-2.C
@@ -0,0 +1,34 @@
+// PR c++/56607
+// { dg-do compile { target { { lp64 || ilp32 } || llp64 } } }
+// { dg-options "-O2 -Wdiv-by-zero -std=c++11" }
+
+constexpr int sc () { return sizeof (char); }
+constexpr int si () { return sizeof (int); }
+constexpr int zc () { return sc () - 1; }
+constexpr int zi (int d) { return si () / d - 1; }
+
+int
+f1 (void)
+{
+  return 1 / zc ();			// { dg-warning "division by zero" }
+}
+
+int
+f2 (void)
+{
+  constexpr int x = zc ();
+  return 1 / x;				// { dg-warning "division by zero" }
+}
+
+int
+f3 (void)
+{
+  return 1 / zi (3);			// { dg-warning "division by zero" }
+}
+
+int
+f4 (void)
+{
+  constexpr int x = zi (3);
+  return 1 / x;				// { dg-warning "division by zero" }
+}