2007-01-07 Manuel Lopez-Ibanez <manu@gcc.gnu.org>

	PR c++/28986
cp/
	* typeck.c (build_binary_op): Call overflow_warning if
	TREE_OVERFLOW_P is true for the result and not for any of the
	operands.

testsuite/
	* g++.dg/conversion/nullptr1.C: Added overflow warning.
	* g++.dg/warn/overflow-warn-1.C: New.
	* g++.dg/warn/overflow-warn-3.C: New.
	* g++.dg/warn/overflow-warn-4.C: New.
	* g++.dg/warn/overflow-warn-5.C: New.
	* g++.dg/warn/overflow-warn-6.C: New.
	* g++.dg/warn/Woverflow-1.C: New.
	* g++.dg/warn/Woverflow-2.C: New.
	* g++.dg/warn/Woverflow-3.C: New.
	* g++.dg/warn/multiple-overflow-warn-2.C: New.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@120558 138bc75d-0d04-0410-961f-82ee72b054a4

13 files changed, 1347 insertions, 1 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index fc2637fc274..0e7898a7de5 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2007-01-07  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR c++/28986
+	* typeck.c (build_binary_op): Call overflow_warning if
+	TREE_OVERFLOW_P is true for the result and not for any of the
+	operands.
+	
 2007-01-06  Lee Millward  <lee.millward@codesourcery.com>
 
        PR c++/19439
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 061241dbf52..2a6c8f88802 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -3870,6 +3870,12 @@ build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
   result = fold_if_not_in_template (result);
   if (final_type != 0)
     result = cp_convert (final_type, result);
+
+  if (TREE_OVERFLOW_P (result) 
+      && !TREE_OVERFLOW_P (op0) 
+      && !TREE_OVERFLOW_P (op1))
+    overflow_warning (result);
+
   return result;
 }
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 3047d1ed28b..a42328a5907 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,17 @@
+2007-01-07  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR c++/28986
+	* g++.dg/conversion/nullptr1.C: Added overflow warning.
+	* g++.dg/warn/overflow-warn-1.C: New.
+	* g++.dg/warn/overflow-warn-3.C: New.
+	* g++.dg/warn/overflow-warn-4.C: New.
+	* g++.dg/warn/overflow-warn-5.C: New.
+	* g++.dg/warn/overflow-warn-6.C: New.
+	* g++.dg/warn/Woverflow-1.C: New.
+	* g++.dg/warn/Woverflow-2.C: New.
+	* g++.dg/warn/Woverflow-3.C: New.
+	* g++.dg/warn/multiple-overflow-warn-2.C: New.
+	
 2007-01-07  Bernhard Fischer  <aldot@gcc.gnu.org>
 
 	PR fortran/27698
diff --git a/gcc/testsuite/g++.dg/conversion/nullptr1.C b/gcc/testsuite/g++.dg/conversion/nullptr1.C
index 6230a2999ef..5e9767a00ee 100644
--- a/gcc/testsuite/g++.dg/conversion/nullptr1.C
+++ b/gcc/testsuite/g++.dg/conversion/nullptr1.C
@@ -6,5 +6,5 @@
 void *p = 0;
 
 void *q = 0 * (INT_MAX + 1);  // { dg-error "invalid conversion" }
-
+// { dg-warning "integer overflow in expression" "" { target *-*-* } 8 }
 
diff --git a/gcc/testsuite/g++.dg/warn/Woverflow-1.C b/gcc/testsuite/g++.dg/warn/Woverflow-1.C
new file mode 100644
index 00000000000..66750472e74
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Woverflow-1.C
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+#include <limits.h>
+
+int foo = INT_MAX + 1;  /* { dg-warning "integer overflow" } */
+
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+#include <limits.h>
+
+int foo = INT_MAX + 1;  /* { dg-warning "integer overflow" } */
+
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+#include <limits.h>
+
+int foo = INT_MAX + 1;  /* { dg-warning "integer overflow" } */
+
diff --git a/gcc/testsuite/g++.dg/warn/Woverflow-2.C b/gcc/testsuite/g++.dg/warn/Woverflow-2.C
new file mode 100644
index 00000000000..392a5ee3e5a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Woverflow-2.C
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Woverflow" } */
+
+#include <limits.h>
+
+int foo = INT_MAX + 1;  /* { dg-warning "integer overflow" } */
+
+/* { dg-do compile } */
+/* { dg-options "-O2 -Woverflow" } */
+
+#include <limits.h>
+
+int foo = INT_MAX + 1;  /* { dg-warning "integer overflow" } */
+
+/* { dg-do compile } */
+/* { dg-options "-O2 -Woverflow" } */
+
+#include <limits.h>
+
+int foo = INT_MAX + 1;  /* { dg-warning "integer overflow" } */
+
diff --git a/gcc/testsuite/g++.dg/warn/Woverflow-3.C b/gcc/testsuite/g++.dg/warn/Woverflow-3.C
new file mode 100644
index 00000000000..d3b8afad416
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Woverflow-3.C
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wno-overflow" } */
+
+#include <limits.h>
+
+int foo = INT_MAX + 1;
+
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wno-overflow" } */
+
+#include <limits.h>
+
+int foo = INT_MAX + 1;
+
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wno-overflow" } */
+
+#include <limits.h>
+
+int foo = INT_MAX + 1;
+
diff --git a/gcc/testsuite/g++.dg/warn/multiple-overflow-warn-2.C b/gcc/testsuite/g++.dg/warn/multiple-overflow-warn-2.C
new file mode 100644
index 00000000000..aa7f40bc793
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/multiple-overflow-warn-2.C
@@ -0,0 +1,36 @@
+/* PR c/19978 : Test for duplicated warnings (binary operators).  */
+/* { dg-do compile } */
+/* { dg-options "-Woverflow" } */
+
+#include <limits.h>
+
+int 
+g1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-bogus "integer overflow in expression.*integer overflow in expression" } */
+  /* { dg-warning "integer overflow in expression" "" { target *-*-* } 10 } */
+}
+/* PR c/19978 : Test for duplicated warnings (binary operators).  */
+/* { dg-do compile } */
+/* { dg-options "-Woverflow" } */
+
+#include <limits.h>
+
+int 
+g1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-bogus "integer overflow in expression.*integer overflow in expression" } */
+  /* { dg-warning "integer overflow in expression" "" { target *-*-* } 10 } */
+}
+/* PR c/19978 : Test for duplicated warnings (binary operators).  */
+/* { dg-do compile } */
+/* { dg-options "-Woverflow" } */
+
+#include <limits.h>
+
+int 
+g1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-bogus "integer overflow in expression.*integer overflow in expression" } */
+  /* { dg-warning "integer overflow in expression" "" { target *-*-* } 10 } */
+}
diff --git a/gcc/testsuite/g++.dg/warn/overflow-warn-1.C b/gcc/testsuite/g++.dg/warn/overflow-warn-1.C
new file mode 100644
index 00000000000..d87774f136a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/overflow-warn-1.C
@@ -0,0 +1,369 @@
+/* Test for diagnostics for constant overflow.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+#include <limits.h>
+
+enum e {
+  E0 = INT_MAX,
+  /* Unsigned overflow wraps around.  */
+  E1 = UINT_MAX + 1,
+  /* Overflow in an unevaluated part of an expression is OK (example
+     in the standard).  */
+  E2 = 2 || 1 / 0, /* { dg-bogus "warning: division by zero" "" { xfail *-*-* } 14 } */
+  E3 = 1 / 0, /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E3' is not an integer constant" "enum error" { target *-*-* } 15 } */
+  /* But as in DR#031, the 1/0 in an evaluated subexpression means the
+     whole expression violates the constraints.  */
+  E4 = 0 * (1 / 0), /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E4' is not an integer constant" "enum error" { xfail *-*-* } 19 } */
+  E5 = INT_MAX + 1, /* { dg-warning "warning: integer overflow in expression" } */
+  /* Again, overflow in evaluated subexpression.  */
+  E6 = 0 * (INT_MAX + 1), /* { dg-warning "warning: integer overflow in expression" } */
+  /* A cast does not constitute overflow in conversion.  */
+  E7 = (char) INT_MAX
+};
+
+struct s {
+  int a;
+  int : 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+  int : 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+};
+
+void
+f (void)
+{
+  /* This expression is not required to be a constant expression, so
+     it should just involve undefined behavior at runtime.  */
+  int c = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+/* This expression is neither required to be constant.  */
+static int sc = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+
+// Test for overflow in null pointer constant.  
+void *n = 0;
+/* The first two of these involve overflow, so are not null pointer
+   constants.  The third has the overflow in an unevaluated
+   subexpression, so is a null pointer constant.  */
+void *p = 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+/* { dg-error "invalid conversion from 'int' to 'void" "null" { target *-*-* } 51 } */
+void *q = 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+/* { dg-error "invalid conversion from 'int' to 'void*'" "null" { xfail *-*-* } 53 } */
+void *r = (1 ? 0 : INT_MAX+1); /* { dg-bogus "integer overflow in expression" "" { xfail *-*-* } 55 } */
+
+void
+g (int i)
+{
+  switch (i)
+    {
+    case 0 * (1/0): /* { dg-warning "warning: division by zero" } */
+      ;
+    case 1 + 0 * (INT_MAX + 1): /* { dg-warning "warning: integer overflow in expression" } */
+      ;
+    }
+}
+
+int
+h (void)
+{
+  return INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int
+h1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+void fuc (unsigned char);
+void fsc (signed char);
+
+void
+h2 (void)
+{
+  fsc (SCHAR_MAX + 1);
+  fsc (SCHAR_MIN - 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX);
+  fsc (UCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fuc (-1);
+  fuc (UCHAR_MAX + 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (SCHAR_MIN);
+  fuc (SCHAR_MIN - 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (-UCHAR_MAX); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+}
+
+void fui (unsigned int);
+void fsi (signed int);
+
+int si;
+unsigned ui;
+
+void
+h2i (int x)
+{
+  /* For some reason, we only give certain warnings for implicit
+     conversions among values of the same precision with -Wconversion,
+     while we don't give others at all.  */
+  fsi ((unsigned)INT_MAX + 1);
+  si = (unsigned)INT_MAX + 1;
+  si = x ? (unsigned)INT_MAX + 1 : 1;
+  fsi ((unsigned)INT_MAX + 2);
+  si = (unsigned)INT_MAX + 2;
+  si = x ? (unsigned)INT_MAX + 2 : 1;
+  fsi (UINT_MAX);
+  si = UINT_MAX;
+  fui (-1);
+  ui = -1;
+  ui = x ? -1 : 1U;
+  fui (INT_MIN);
+  ui = INT_MIN;
+  ui = x ? INT_MIN : 1U;
+}
+/* Test for diagnostics for constant overflow.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+#include <limits.h>
+
+enum e {
+  E0 = INT_MAX,
+  /* Unsigned overflow wraps around.  */
+  E1 = UINT_MAX + 1,
+  /* Overflow in an unevaluated part of an expression is OK (example
+     in the standard).  */
+  E2 = 2 || 1 / 0, /* { dg-bogus "warning: division by zero" "" { xfail *-*-* } 14 } */
+  E3 = 1 / 0, /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E3' is not an integer constant" "enum error" { target *-*-* } 15 } */
+  /* But as in DR#031, the 1/0 in an evaluated subexpression means the
+     whole expression violates the constraints.  */
+  E4 = 0 * (1 / 0), /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E4' is not an integer constant" "enum error" { xfail *-*-* } 19 } */
+  E5 = INT_MAX + 1, /* { dg-warning "warning: integer overflow in expression" } */
+  /* Again, overflow in evaluated subexpression.  */
+  E6 = 0 * (INT_MAX + 1), /* { dg-warning "warning: integer overflow in expression" } */
+  /* A cast does not constitute overflow in conversion.  */
+  E7 = (char) INT_MAX
+};
+
+struct s {
+  int a;
+  int : 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+  int : 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+};
+
+void
+f (void)
+{
+  /* This expression is not required to be a constant expression, so
+     it should just involve undefined behavior at runtime.  */
+  int c = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+/* But this expression does need to be constant.  */
+static int sc = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+/* The first two of these involve overflow, so are not null pointer
+   constants.  The third has the overflow in an unevaluated
+   subexpression, so is a null pointer constant.  */
+void *p = 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+/* { dg-error "invalid conversion from 'int' to 'void" "null" { target *-*-* } 48 } */
+void *q = 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+/* { dg-error "invalid conversion from 'int' to 'void*'" "null" { xfail *-*-* } 50 } */
+void *r = (1 ? 0 : INT_MAX+1); /* { dg-bogus "integer overflow in expression" "" { xfail *-*-* } 52 } */
+
+void
+g (int i)
+{
+  switch (i)
+    {
+    case 0 * (1/0): /* { dg-warning "warning: division by zero" } */
+      ;
+    case 1 + 0 * (INT_MAX + 1): /* { dg-warning "warning: integer overflow in expression" } */
+      ;
+    }
+}
+
+int
+h (void)
+{
+  return INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int
+h1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+void fuc (unsigned char);
+void fsc (signed char);
+
+void
+h2 (void)
+{
+  fsc (SCHAR_MAX + 1);
+  fsc (SCHAR_MIN - 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX);
+  fsc (UCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fuc (-1);
+  fuc (UCHAR_MAX + 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (SCHAR_MIN);
+  fuc (SCHAR_MIN - 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (-UCHAR_MAX); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+}
+
+void fui (unsigned int);
+void fsi (signed int);
+
+int si;
+unsigned ui;
+
+void
+h2i (int x)
+{
+  /* For some reason, we only give certain warnings for implicit
+     conversions among values of the same precision with -Wconversion,
+     while we don't give others at all.  */
+  fsi ((unsigned)INT_MAX + 1);
+  si = (unsigned)INT_MAX + 1;
+  si = x ? (unsigned)INT_MAX + 1 : 1;
+  fsi ((unsigned)INT_MAX + 2);
+  si = (unsigned)INT_MAX + 2;
+  si = x ? (unsigned)INT_MAX + 2 : 1;
+  fsi (UINT_MAX);
+  si = UINT_MAX;
+  fui (-1);
+  ui = -1;
+  ui = x ? -1 : 1U;
+  fui (INT_MIN);
+  ui = INT_MIN;
+  ui = x ? INT_MIN : 1U;
+}
+/* Test for diagnostics for constant overflow.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+#include <limits.h>
+
+enum e {
+  E0 = INT_MAX,
+  /* Unsigned overflow wraps around.  */
+  E1 = UINT_MAX + 1,
+  /* Overflow in an unevaluated part of an expression is OK (example
+     in the standard).  */
+  E2 = 2 || 1 / 0, /* { dg-bogus "warning: division by zero" "" { xfail *-*-* } 14 } */
+  E3 = 1 / 0, /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E3' is not an integer constant" "enum error" { target *-*-* } 15 } */
+  /* But as in DR#031, the 1/0 in an evaluated subexpression means the
+     whole expression violates the constraints.  */
+  E4 = 0 * (1 / 0), /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E4' is not an integer constant" "enum error" { xfail *-*-* } 19 } */
+  E5 = INT_MAX + 1, /* { dg-warning "warning: integer overflow in expression" } */
+  /* Again, overflow in evaluated subexpression.  */
+  E6 = 0 * (INT_MAX + 1), /* { dg-warning "warning: integer overflow in expression" } */
+  /* A cast does not constitute overflow in conversion.  */
+  E7 = (char) INT_MAX
+};
+
+struct s {
+  int a;
+  int : 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+  int : 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+};
+
+void
+f (void)
+{
+  /* This expression is not required to be a constant expression, so
+     it should just involve undefined behavior at runtime.  */
+  int c = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+/* This expression is neither required to be constant.  */
+static int sc = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+
+// Test for overflow in null pointer constant.  
+void *n = 0;
+/* The first two of these involve overflow, so are not null pointer
+   constants.  The third has the overflow in an unevaluated
+   subexpression, so is a null pointer constant.  */
+void *p = 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+/* { dg-error "invalid conversion from 'int' to 'void" "null" { target *-*-* } 51 } */
+void *q = 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+/* { dg-error "invalid conversion from 'int' to 'void*'" "null" { xfail *-*-* } 53 } */
+void *r = (1 ? 0 : INT_MAX+1); /* { dg-bogus "integer overflow in expression" "" { xfail *-*-* } 55 } */
+
+void
+g (int i)
+{
+  switch (i)
+    {
+    case 0 * (1/0): /* { dg-warning "warning: division by zero" } */
+      ;
+    case 1 + 0 * (INT_MAX + 1): /* { dg-warning "warning: integer overflow in expression" } */
+      ;
+    }
+}
+
+int
+h (void)
+{
+  return INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int
+h1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+void fuc (unsigned char);
+void fsc (signed char);
+
+void
+h2 (void)
+{
+  fsc (SCHAR_MAX + 1);
+  fsc (SCHAR_MIN - 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX);
+  fsc (UCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fuc (-1);
+  fuc (UCHAR_MAX + 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (SCHAR_MIN);
+  fuc (SCHAR_MIN - 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (-UCHAR_MAX); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+}
+
+void fui (unsigned int);
+void fsi (signed int);
+
+int si;
+unsigned ui;
+
+void
+h2i (int x)
+{
+  /* For some reason, we only give certain warnings for implicit
+     conversions among values of the same precision with -Wconversion,
+     while we don't give others at all.  */
+  fsi ((unsigned)INT_MAX + 1);
+  si = (unsigned)INT_MAX + 1;
+  si = x ? (unsigned)INT_MAX + 1 : 1;
+  fsi ((unsigned)INT_MAX + 2);
+  si = (unsigned)INT_MAX + 2;
+  si = x ? (unsigned)INT_MAX + 2 : 1;
+  fsi (UINT_MAX);
+  si = UINT_MAX;
+  fui (-1);
+  ui = -1;
+  ui = x ? -1 : 1U;
+  fui (INT_MIN);
+  ui = INT_MIN;
+  ui = x ? INT_MIN : 1U;
+}
diff --git a/gcc/testsuite/g++.dg/warn/overflow-warn-3.C b/gcc/testsuite/g++.dg/warn/overflow-warn-3.C
new file mode 100644
index 00000000000..a8651c9f645
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/overflow-warn-3.C
@@ -0,0 +1,388 @@
+/* Test for diagnostics for constant overflow.  Test with -pedantic.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-fpermissive -pedantic" } */
+
+#include <limits.h>
+
+enum e {
+  E0 = INT_MAX,
+  /* Unsigned overflow wraps around.  */
+  E1 = UINT_MAX + 1,
+  /* Overflow in an unevaluated part of an expression is OK (example
+     in the standard).  */
+  E2 = 2 || 1 / 0, /* { dg-bogus "warning: division by zero" "" { xfail *-*-* } 14 } */
+  E3 = 1 / 0, /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E3' is not an integer constant" "enum error" { target *-*-* } 15 } */
+  /* But as in DR#031, the 1/0 in an evaluated subexpression means the
+     whole expression violates the constraints.  */
+  E4 = 0 * (1 / 0), /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E4' is not an integer constant" "enum error" { xfail *-*-* } 19 } */
+  E5 = INT_MAX + 1, /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 21 } */
+  /* Again, overflow in evaluated subexpression.  */
+  E6 = 0 * (INT_MAX + 1), /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 24 } */
+  /* A cast does not constitute overflow in conversion.  */
+  E7 = (char) INT_MAX
+};
+
+struct s {
+  int a;
+  int : 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+  int : 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 33 } */
+};
+
+void
+f (void)
+{
+  /* This expression is not required to be a constant expression, so
+     it should just involve undefined behavior at runtime.  */
+  int c = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+}
+
+/* This expression is neither required to be constant.  */
+static int sc = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+
+// Test for overflow in null pointer constant.  
+void *n = 0;
+/* The first two of these involve overflow, so are not null pointer
+   constants.  The third has the overflow in an unevaluated
+   subexpression, so is a null pointer constant.  */
+void *p = 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+/* { dg-error "invalid conversion from 'int' to 'void" "null" { target *-*-* } 55 } */
+
+void *q = 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+/* { dg-error "invalid conversion from 'int' to 'void*'" "null" { xfail *-*-* } 58 } */
+void *r = (1 ? 0 : INT_MAX+1); /* { dg-bogus "integer overflow in expression" "" { xfail *-*-* } 60 } */
+
+void
+g (int i)
+{
+  switch (i)
+    {
+    case 0 * (1/0): /* { dg-warning "warning: division by zero" } */
+      ;
+    case 1 + 0 * (INT_MAX + 1): /* { dg-warning "warning: integer overflow in expression" } */
+      /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 69 } */
+      ;
+    }
+}
+
+int
+h (void)
+{
+  return INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int
+h1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+void fuc (unsigned char);
+void fsc (signed char);
+
+void
+h2 (void)
+{
+  fsc (SCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (SCHAR_MIN - 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fuc (-1);
+  fuc (UCHAR_MAX + 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (SCHAR_MIN);
+  fuc (SCHAR_MIN - 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (-UCHAR_MAX); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+}
+
+void fui (unsigned int);
+void fsi (signed int);
+
+int si;
+unsigned ui;
+
+void
+h2i (int x)
+{
+  /* For some reason, we only give certain warnings for implicit
+     conversions among values of the same precision with -Wconversion,
+     while we don't give others at all.  */
+  fsi ((unsigned)INT_MAX + 1);
+  si = (unsigned)INT_MAX + 1;
+  si = x ? (unsigned)INT_MAX + 1 : 1;
+  fsi ((unsigned)INT_MAX + 2);
+  si = (unsigned)INT_MAX + 2;
+  si = x ? (unsigned)INT_MAX + 2 : 1;
+  fsi (UINT_MAX);
+  si = UINT_MAX;
+  fui (-1);
+  ui = -1;
+  ui = x ? -1 : 1U;
+  fui (INT_MIN);
+  ui = INT_MIN;
+  ui = x ? INT_MIN : 1U;
+}
+/* Test for diagnostics for constant overflow.  Test with -pedantic.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-fpermissive -pedantic" } */
+
+#include <limits.h>
+
+enum e {
+  E0 = INT_MAX,
+  /* Unsigned overflow wraps around.  */
+  E1 = UINT_MAX + 1,
+  /* Overflow in an unevaluated part of an expression is OK (example
+     in the standard).  */
+  E2 = 2 || 1 / 0, /* { dg-bogus "warning: division by zero" "" { xfail *-*-* } 14 } */
+  E3 = 1 / 0, /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E3' is not an integer constant" "enum error" { target *-*-* } 15 } */
+  /* But as in DR#031, the 1/0 in an evaluated subexpression means the
+     whole expression violates the constraints.  */
+  E4 = 0 * (1 / 0), /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E4' is not an integer constant" "enum error" { xfail *-*-* } 19 } */
+  E5 = INT_MAX + 1, /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 21 } */
+  /* Again, overflow in evaluated subexpression.  */
+  E6 = 0 * (INT_MAX + 1), /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 24 } */
+  /* A cast does not constitute overflow in conversion.  */
+  E7 = (char) INT_MAX
+};
+
+struct s {
+  int a;
+  int : 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+  int : 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 33 } */
+};
+
+void
+f (void)
+{
+  /* This expression is not required to be a constant expression, so
+     it should just involve undefined behavior at runtime.  */
+  int c = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+}
+
+/* But this expression does need to be constant (in C++ ???).  */
+static int sc = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+/* { dg-warning "warning: overflow in constant expression" "constant" { xfail *-*-* } 47 } */
+
+/* The first two of these involve overflow, so are not null pointer
+   constants.  The third has the overflow in an unevaluated
+   subexpression, so is a null pointer constant.  */
+void *p = 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+/* { dg-error "invalid conversion from 'int' to 'void" "null" { target *-*-* } 53 } */
+
+void *q = 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+/* { dg-error "invalid conversion from 'int' to 'void*'" "null" { xfail *-*-* } 56 } */
+void *r = (1 ? 0 : INT_MAX+1); /* { dg-bogus "integer overflow in expression" "" { xfail *-*-* } 58 } */
+
+void
+g (int i)
+{
+  switch (i)
+    {
+    case 0 * (1/0): /* { dg-warning "warning: division by zero" } */
+      ;
+    case 1 + 0 * (INT_MAX + 1): /* { dg-warning "warning: integer overflow in expression" } */
+      /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 67 } */
+      ;
+    }
+}
+
+int
+h (void)
+{
+  return INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int
+h1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+void fuc (unsigned char);
+void fsc (signed char);
+
+void
+h2 (void)
+{
+  fsc (SCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (SCHAR_MIN - 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fuc (-1);
+  fuc (UCHAR_MAX + 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (SCHAR_MIN);
+  fuc (SCHAR_MIN - 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (-UCHAR_MAX); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+}
+
+void fui (unsigned int);
+void fsi (signed int);
+
+int si;
+unsigned ui;
+
+void
+h2i (int x)
+{
+  /* For some reason, we only give certain warnings for implicit
+     conversions among values of the same precision with -Wconversion,
+     while we don't give others at all.  */
+  fsi ((unsigned)INT_MAX + 1);
+  si = (unsigned)INT_MAX + 1;
+  si = x ? (unsigned)INT_MAX + 1 : 1;
+  fsi ((unsigned)INT_MAX + 2);
+  si = (unsigned)INT_MAX + 2;
+  si = x ? (unsigned)INT_MAX + 2 : 1;
+  fsi (UINT_MAX);
+  si = UINT_MAX;
+  fui (-1);
+  ui = -1;
+  ui = x ? -1 : 1U;
+  fui (INT_MIN);
+  ui = INT_MIN;
+  ui = x ? INT_MIN : 1U;
+}
+/* Test for diagnostics for constant overflow.  Test with -pedantic.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-fpermissive -pedantic" } */
+
+#include <limits.h>
+
+enum e {
+  E0 = INT_MAX,
+  /* Unsigned overflow wraps around.  */
+  E1 = UINT_MAX + 1,
+  /* Overflow in an unevaluated part of an expression is OK (example
+     in the standard).  */
+  E2 = 2 || 1 / 0, /* { dg-bogus "warning: division by zero" "" { xfail *-*-* } 14 } */
+  E3 = 1 / 0, /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E3' is not an integer constant" "enum error" { target *-*-* } 15 } */
+  /* But as in DR#031, the 1/0 in an evaluated subexpression means the
+     whole expression violates the constraints.  */
+  E4 = 0 * (1 / 0), /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E4' is not an integer constant" "enum error" { xfail *-*-* } 19 } */
+  E5 = INT_MAX + 1, /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 21 } */
+  /* Again, overflow in evaluated subexpression.  */
+  E6 = 0 * (INT_MAX + 1), /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 24 } */
+  /* A cast does not constitute overflow in conversion.  */
+  E7 = (char) INT_MAX
+};
+
+struct s {
+  int a;
+  int : 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+  int : 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 33 } */
+};
+
+void
+f (void)
+{
+  /* This expression is not required to be a constant expression, so
+     it should just involve undefined behavior at runtime.  */
+  int c = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+}
+
+/* This expression is neither required to be constant.  */
+static int sc = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+
+// Test for overflow in null pointer constant.  
+void *n = 0;
+/* The first two of these involve overflow, so are not null pointer
+   constants.  The third has the overflow in an unevaluated
+   subexpression, so is a null pointer constant.  */
+void *p = 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+/* { dg-error "invalid conversion from 'int' to 'void" "null" { target *-*-* } 55 } */
+
+void *q = 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+/* { dg-error "invalid conversion from 'int' to 'void*'" "null" { xfail *-*-* } 58 } */
+void *r = (1 ? 0 : INT_MAX+1); /* { dg-bogus "integer overflow in expression" "" { xfail *-*-* } 60 } */
+
+void
+g (int i)
+{
+  switch (i)
+    {
+    case 0 * (1/0): /* { dg-warning "warning: division by zero" } */
+      ;
+    case 1 + 0 * (INT_MAX + 1): /* { dg-warning "warning: integer overflow in expression" } */
+      /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 69 } */
+      ;
+    }
+}
+
+int
+h (void)
+{
+  return INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int
+h1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+void fuc (unsigned char);
+void fsc (signed char);
+
+void
+h2 (void)
+{
+  fsc (SCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (SCHAR_MIN - 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fuc (-1);
+  fuc (UCHAR_MAX + 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (SCHAR_MIN);
+  fuc (SCHAR_MIN - 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (-UCHAR_MAX); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+}
+
+void fui (unsigned int);
+void fsi (signed int);
+
+int si;
+unsigned ui;
+
+void
+h2i (int x)
+{
+  /* For some reason, we only give certain warnings for implicit
+     conversions among values of the same precision with -Wconversion,
+     while we don't give others at all.  */
+  fsi ((unsigned)INT_MAX + 1);
+  si = (unsigned)INT_MAX + 1;
+  si = x ? (unsigned)INT_MAX + 1 : 1;
+  fsi ((unsigned)INT_MAX + 2);
+  si = (unsigned)INT_MAX + 2;
+  si = x ? (unsigned)INT_MAX + 2 : 1;
+  fsi (UINT_MAX);
+  si = UINT_MAX;
+  fui (-1);
+  ui = -1;
+  ui = x ? -1 : 1U;
+  fui (INT_MIN);
+  ui = INT_MIN;
+  ui = x ? INT_MIN : 1U;
+}
diff --git a/gcc/testsuite/g++.dg/warn/overflow-warn-4.C b/gcc/testsuite/g++.dg/warn/overflow-warn-4.C
new file mode 100644
index 00000000000..4d4ecf0bf02
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/overflow-warn-4.C
@@ -0,0 +1,388 @@
+/* Test for diagnostics for constant overflow.  Test with -pedantic-errors.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-pedantic-errors" } */
+
+#include <limits.h>
+
+enum e {
+  E0 = INT_MAX,
+  /* Unsigned overflow wraps around.  */
+  E1 = UINT_MAX + 1,
+  /* Overflow in an unevaluated part of an expression is OK (example
+     in the standard).  */
+  E2 = 2 || 1 / 0, /* { dg-bogus "warning: division by zero" "" { xfail *-*-* } 14 } */
+  E3 = 1 / 0, /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E3' is not an integer constant" "enum error" { target *-*-* } 15 } */
+  /* But as in DR#031, the 1/0 in an evaluated subexpression means the
+     whole expression violates the constraints.  */
+  E4 = 0 * (1 / 0), /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E4' is not an integer constant" "enum error" { xfail *-*-* } 19 } */
+  E5 = INT_MAX + 1, /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 21 } */
+  /* Again, overflow in evaluated subexpression.  */
+  E6 = 0 * (INT_MAX + 1), /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 24 } */
+  /* A cast does not constitute overflow in conversion.  */
+  E7 = (char) INT_MAX
+};
+
+struct s {
+  int a;
+  int : 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+  int : 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 33 } */
+};
+
+void
+f (void)
+{
+  /* This expression is not required to be a constant expression, so
+     it should just involve undefined behavior at runtime.  */
+  int c = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+}
+
+/* This expression is neither required to be constant.  */
+static int sc = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+
+// Test for overflow in null pointer constant.  
+void *n = 0;
+/* The first two of these involve overflow, so are not null pointer
+   constants.  The third has the overflow in an unevaluated
+   subexpression, so is a null pointer constant.  */
+void *p = 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+/* { dg-error "invalid conversion from 'int' to 'void" "null" { target *-*-* } 55 } */
+
+void *q = 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+/* { dg-error "invalid conversion from 'int' to 'void*'" "null" { xfail *-*-* } 58 } */
+void *r = (1 ? 0 : INT_MAX+1); /* { dg-bogus "integer overflow in expression" "" { xfail *-*-* } 60 } */
+
+void
+g (int i)
+{
+  switch (i)
+    {
+    case 0 * (1/0): /* { dg-warning "warning: division by zero" } */
+      ;
+    case 1 + 0 * (INT_MAX + 1): /* { dg-warning "warning: integer overflow in expression" } */
+      /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 69 } */
+      ;
+    }
+}
+
+int
+h (void)
+{
+  return INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int
+h1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+void fuc (unsigned char);
+void fsc (signed char);
+
+void
+h2 (void)
+{
+  fsc (SCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (SCHAR_MIN - 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fuc (-1);
+  fuc (UCHAR_MAX + 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (SCHAR_MIN);
+  fuc (SCHAR_MIN - 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (-UCHAR_MAX); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+}
+
+void fui (unsigned int);
+void fsi (signed int);
+
+int si;
+unsigned ui;
+
+void
+h2i (int x)
+{
+  /* For some reason, we only give certain warnings for implicit
+     conversions among values of the same precision with -Wconversion,
+     while we don't give others at all.  */
+  fsi ((unsigned)INT_MAX + 1);
+  si = (unsigned)INT_MAX + 1;
+  si = x ? (unsigned)INT_MAX + 1 : 1;
+  fsi ((unsigned)INT_MAX + 2);
+  si = (unsigned)INT_MAX + 2;
+  si = x ? (unsigned)INT_MAX + 2 : 1;
+  fsi (UINT_MAX);
+  si = UINT_MAX;
+  fui (-1);
+  ui = -1;
+  ui = x ? -1 : 1U;
+  fui (INT_MIN);
+  ui = INT_MIN;
+  ui = x ? INT_MIN : 1U;
+}
+/* Test for diagnostics for constant overflow.  Test with -pedantic-errors.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-pedantic-errors" } */
+
+#include <limits.h>
+
+enum e {
+  E0 = INT_MAX,
+  /* Unsigned overflow wraps around.  */
+  E1 = UINT_MAX + 1,
+  /* Overflow in an unevaluated part of an expression is OK (example
+     in the standard).  */
+  E2 = 2 || 1 / 0, /* { dg-bogus "warning: division by zero" "" { xfail *-*-* } 14 } */
+  E3 = 1 / 0, /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E3' is not an integer constant" "enum error" { target *-*-* } 15 } */
+  /* But as in DR#031, the 1/0 in an evaluated subexpression means the
+     whole expression violates the constraints.  */
+  E4 = 0 * (1 / 0), /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E4' is not an integer constant" "enum error" { xfail *-*-* } 19 } */
+  E5 = INT_MAX + 1, /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 21 } */
+  /* Again, overflow in evaluated subexpression.  */
+  E6 = 0 * (INT_MAX + 1), /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 24 } */
+  /* A cast does not constitute overflow in conversion.  */
+  E7 = (char) INT_MAX
+};
+
+struct s {
+  int a;
+  int : 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+  int : 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 33 } */
+};
+
+void
+f (void)
+{
+  /* This expression is not required to be a constant expression, so
+     it should just involve undefined behavior at runtime.  */
+  int c = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+}
+
+/* But this expression does need to be constant (in C++ ???).  */
+static int sc = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+/* { dg-error "error: overflow in constant expression" "constant" { xfail *-*-* } 47 } */
+
+/* The first two of these involve overflow, so are not null pointer
+   constants.  The third has the overflow in an unevaluated
+   subexpression, so is a null pointer constant.  */
+void *p = 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+/* { dg-error "invalid conversion from 'int' to 'void" "null" { target *-*-* } 53 } */
+
+void *q = 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+/* { dg-error "invalid conversion from 'int' to 'void*'" "null" { xfail *-*-* } 56 } */
+void *r = (1 ? 0 : INT_MAX+1); /* { dg-bogus "integer overflow in expression" "" { xfail *-*-* } 58 } */
+
+void
+g (int i)
+{
+  switch (i)
+    {
+    case 0 * (1/0): /* { dg-warning "warning: division by zero" } */
+      ;
+    case 1 + 0 * (INT_MAX + 1): /* { dg-warning "warning: integer overflow in expression" } */
+      /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 67 } */
+      ;
+    }
+}
+
+int
+h (void)
+{
+  return INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int
+h1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+void fuc (unsigned char);
+void fsc (signed char);
+
+void
+h2 (void)
+{
+  fsc (SCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (SCHAR_MIN - 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fuc (-1);
+  fuc (UCHAR_MAX + 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (SCHAR_MIN);
+  fuc (SCHAR_MIN - 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (-UCHAR_MAX); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+}
+
+void fui (unsigned int);
+void fsi (signed int);
+
+int si;
+unsigned ui;
+
+void
+h2i (int x)
+{
+  /* For some reason, we only give certain warnings for implicit
+     conversions among values of the same precision with -Wconversion,
+     while we don't give others at all.  */
+  fsi ((unsigned)INT_MAX + 1);
+  si = (unsigned)INT_MAX + 1;
+  si = x ? (unsigned)INT_MAX + 1 : 1;
+  fsi ((unsigned)INT_MAX + 2);
+  si = (unsigned)INT_MAX + 2;
+  si = x ? (unsigned)INT_MAX + 2 : 1;
+  fsi (UINT_MAX);
+  si = UINT_MAX;
+  fui (-1);
+  ui = -1;
+  ui = x ? -1 : 1U;
+  fui (INT_MIN);
+  ui = INT_MIN;
+  ui = x ? INT_MIN : 1U;
+}
+/* Test for diagnostics for constant overflow.  Test with -pedantic-errors.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-pedantic-errors" } */
+
+#include <limits.h>
+
+enum e {
+  E0 = INT_MAX,
+  /* Unsigned overflow wraps around.  */
+  E1 = UINT_MAX + 1,
+  /* Overflow in an unevaluated part of an expression is OK (example
+     in the standard).  */
+  E2 = 2 || 1 / 0, /* { dg-bogus "warning: division by zero" "" { xfail *-*-* } 14 } */
+  E3 = 1 / 0, /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E3' is not an integer constant" "enum error" { target *-*-* } 15 } */
+  /* But as in DR#031, the 1/0 in an evaluated subexpression means the
+     whole expression violates the constraints.  */
+  E4 = 0 * (1 / 0), /* { dg-warning "warning: division by zero" } */
+  /* { dg-error "error: enumerator value for 'E4' is not an integer constant" "enum error" { xfail *-*-* } 19 } */
+  E5 = INT_MAX + 1, /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 21 } */
+  /* Again, overflow in evaluated subexpression.  */
+  E6 = 0 * (INT_MAX + 1), /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 24 } */
+  /* A cast does not constitute overflow in conversion.  */
+  E7 = (char) INT_MAX
+};
+
+struct s {
+  int a;
+  int : 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+  int : 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+  /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 33 } */
+};
+
+void
+f (void)
+{
+  /* This expression is not required to be a constant expression, so
+     it should just involve undefined behavior at runtime.  */
+  int c = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+}
+
+/* This expression is neither required to be constant.  */
+static int sc = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+
+
+// Test for overflow in null pointer constant.  
+void *n = 0;
+/* The first two of these involve overflow, so are not null pointer
+   constants.  The third has the overflow in an unevaluated
+   subexpression, so is a null pointer constant.  */
+void *p = 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
+/* { dg-error "invalid conversion from 'int' to 'void" "null" { target *-*-* } 55 } */
+
+void *q = 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
+/* { dg-error "invalid conversion from 'int' to 'void*'" "null" { xfail *-*-* } 58 } */
+void *r = (1 ? 0 : INT_MAX+1); /* { dg-bogus "integer overflow in expression" "" { xfail *-*-* } 60 } */
+
+void
+g (int i)
+{
+  switch (i)
+    {
+    case 0 * (1/0): /* { dg-warning "warning: division by zero" } */
+      ;
+    case 1 + 0 * (INT_MAX + 1): /* { dg-warning "warning: integer overflow in expression" } */
+      /* { dg-error "error: overflow in constant expression" "constant" { target *-*-* } 69 } */
+      ;
+    }
+}
+
+int
+h (void)
+{
+  return INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int
+h1 (void)
+{
+  return INT_MAX + 1 - INT_MAX; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+void fuc (unsigned char);
+void fsc (signed char);
+
+void
+h2 (void)
+{
+  fsc (SCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (SCHAR_MIN - 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fsc (UCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
+  fuc (-1);
+  fuc (UCHAR_MAX + 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (SCHAR_MIN);
+  fuc (SCHAR_MIN - 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+  fuc (-UCHAR_MAX); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
+}
+
+void fui (unsigned int);
+void fsi (signed int);
+
+int si;
+unsigned ui;
+
+void
+h2i (int x)
+{
+  /* For some reason, we only give certain warnings for implicit
+     conversions among values of the same precision with -Wconversion,
+     while we don't give others at all.  */
+  fsi ((unsigned)INT_MAX + 1);
+  si = (unsigned)INT_MAX + 1;
+  si = x ? (unsigned)INT_MAX + 1 : 1;
+  fsi ((unsigned)INT_MAX + 2);
+  si = (unsigned)INT_MAX + 2;
+  si = x ? (unsigned)INT_MAX + 2 : 1;
+  fsi (UINT_MAX);
+  si = UINT_MAX;
+  fui (-1);
+  ui = -1;
+  ui = x ? -1 : 1U;
+  fui (INT_MIN);
+  ui = INT_MIN;
+  ui = x ? INT_MIN : 1U;
+}
diff --git a/gcc/testsuite/g++.dg/warn/overflow-warn-5.C b/gcc/testsuite/g++.dg/warn/overflow-warn-5.C
new file mode 100644
index 00000000000..5fd0ac4f93c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/overflow-warn-5.C
@@ -0,0 +1,21 @@
+/* PR c/27273 */
+/* { dg-do compile } */
+/* { dg-options "-Woverflow" } */
+
+unsigned char rx_async(unsigned char p) {
+    return p & 512; /* { dg-warning "overflow in implicit constant conversion" } */
+}
+/* PR c/27273 */
+/* { dg-do compile } */
+/* { dg-options "-Woverflow" } */
+
+unsigned char rx_async(unsigned char p) {
+    return p & 512; /* { dg-warning "overflow in implicit constant conversion" } */
+}
+/* PR c/27273 */
+/* { dg-do compile } */
+/* { dg-options "-Woverflow" } */
+
+unsigned char rx_async(unsigned char p) {
+    return p & 512; /* { dg-warning "overflow in implicit constant conversion" } */
+}
diff --git a/gcc/testsuite/g++.dg/warn/overflow-warn-6.C b/gcc/testsuite/g++.dg/warn/overflow-warn-6.C
new file mode 100644
index 00000000000..af549abb54f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/overflow-warn-6.C
@@ -0,0 +1,54 @@
+/* Test non-constant operands in overflowed expressions.  */
+/* { dg-do compile } */
+/* { dg-options "-Woverflow" } */
+
+#include <limits.h>
+
+int 
+h1 (int x)
+{
+  return x * (0 * (INT_MAX + 1)); /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int 
+h2 (int x)
+{
+  return ((INT_MAX + 1) * 0) * x; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+/* Test non-constant operands in overflowed expressions.  */
+/* { dg-do compile } */
+/* { dg-options "-Woverflow" } */
+
+#include <limits.h>
+
+int 
+h1 (int x)
+{
+  return x * (0 * (INT_MAX + 1)); /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int 
+h2 (int x)
+{
+  return ((INT_MAX + 1) * 0) * x; /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+/* Test non-constant operands in overflowed expressions.  */
+/* { dg-do compile } */
+/* { dg-options "-Woverflow" } */
+
+#include <limits.h>
+
+int 
+h1 (int x)
+{
+  return x * (0 * (INT_MAX + 1)); /* { dg-warning "warning: integer overflow in expression" } */
+}
+
+int 
+h2 (int x)
+{
+  return ((INT_MAX + 1) * 0) * x; /* { dg-warning "warning: integer overflow in expression" } */
+}
+