re PR c/39613 (gcc 20090331 produces an error at mce64.c in kernel 2.6.29)

	PR c/39613
	* c-typeck.c (do_case): If case label is not an INTEGER_CST, fold
	it and pedwarn if this results in an INTEGER_CST.

testsuite:
	* gcc.dg/case-const-1.c, gcc.dg/case-const-2.c,
	gcc.dg/case-const-3.c: New tests.

From-SVN: r145793

gcc/ChangeLog

+2009-04-09  Joseph Myers  <joseph@codesourcery.com>
+
+	PR c/39613
+	* c-typeck.c (do_case): If case label is not an INTEGER_CST, fold
+	it and pedwarn if this results in an INTEGER_CST.
+
 2009-04-08  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
 	* doc/install.texi: Update minimum GMP version.  Remove obsolete

gcc/c-typeck.c

@@ -7851,6 +7851,22 @@ do_case (tree low_value, tree high_value)
 {
   tree label = NULL_TREE;
 
+  if (low_value && TREE_CODE (low_value) != INTEGER_CST)
+    {
+      low_value = c_fully_fold (low_value, false, NULL);
+      if (TREE_CODE (low_value) == INTEGER_CST)
+	pedwarn (input_location, OPT_pedantic,
+		 "case label is not an integer constant expression");
+    }
+
+  if (high_value && TREE_CODE (high_value) != INTEGER_CST)
+    {
+      high_value = c_fully_fold (high_value, false, NULL);
+      if (TREE_CODE (high_value) == INTEGER_CST)
+	pedwarn (input_location, OPT_pedantic,
+		 "case label is not an integer constant expression");
+    }
+
   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
       && !c_switch_stack->blocked_vm)
     {

gcc/testsuite/ChangeLog

+2009-04-09  Joseph Myers  <joseph@codesourcery.com>
+
+	PR c/39613
+	* gcc.dg/case-const-1.c, gcc.dg/case-const-2.c,
+	gcc.dg/case-const-3.c: New tests.
+
 2009-04-08  Joseph Myers  <joseph@codesourcery.com>
 
 	* gcc.dg/c99-stdint-1.c: Fix cut-and-paste mistakes in test.

gcc/testsuite/gcc.dg/case-const-1.c

+/* Test for case labels not integer constant expressions but folding
+   to integer constants (used in Linux kernel, PR 39613).  */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+extern int i;
+void
+f (int c)
+{
+  switch (c)
+    {
+    case (1 ? 1 : i):
+      ;
+    }
+}

gcc/testsuite/gcc.dg/case-const-2.c

+/* Test for case labels not integer constant expressions but folding
+   to integer constants (used in Linux kernel, PR 39613).  */
+/* { dg-do compile } */
+/* { dg-options "-pedantic" } */
+
+extern int i;
+void
+f (int c)
+{
+  switch (c)
+    {
+    case (1 ? 1 : i): /* { dg-warning "case label is not an integer constant expression" } */
+      ;
+    }
+}

gcc/testsuite/gcc.dg/case-const-3.c

+/* Test for case labels not integer constant expressions but folding
+   to integer constants (used in Linux kernel, PR 39613).  */
+/* { dg-do compile } */
+/* { dg-options "-pedantic-errors" } */
+
+extern int i;
+void
+f (int c)
+{
+  switch (c)
+    {
+    case (1 ? 1 : i): /* { dg-error "case label is not an integer constant expression" } */
+      ;
+    }
+}