expr.c (expand_expr): Force overflows into registers.

* expr.c (expand_expr) [INTEGER_CST]: Force overflows into registers.

	* gcc.c-torture/compile/20020409-1.c: New.

From-SVN: r52104

gcc/ChangeLog

@@ -1,3 +1,8 @@
+2002-04-09  Richard Henderson  <rth@redhat.com>
+
+	PR c/5078
+	* expr.c (expand_expr) [INTEGER_CST]: Force overflows into registers.
+
 2002-04-09  Richard Henderson  <rth@redhat.com>
 
 	* basic-block.h (flow_delete_block_noexpunge): Declare.

gcc/expr.c

@@ -6318,9 +6318,19 @@ expand_expr (exp, target, tmode, modifier)
       return DECL_RTL (exp);
 
     case INTEGER_CST:
-      return immed_double_const (TREE_INT_CST_LOW (exp),
+      temp = immed_double_const (TREE_INT_CST_LOW (exp),
 				 TREE_INT_CST_HIGH (exp), mode);
 
+      /* ??? If overflow is set, fold will have done an incomplete job,
+	 which can result in (plus xx (const_int 0)), which can get
+	 simplified by validate_replace_rtx during virtual register
+	 instantiation, which can result in unrecognizable insns.
+	 Avoid this by forcing all overflows into registers.  */
+      if (TREE_CONSTANT_OVERFLOW (exp))
+	temp = force_reg (mode, temp);
+
+      return temp;
+
     case CONST_DECL:
       return expand_expr (DECL_INITIAL (exp), target, VOIDmode, 0);
 

gcc/testsuite/gcc.c-torture/compile/20020409-1.c

@@ -0,0 +1,9 @@
+/* PR c/5078 */
+
+#include <limits.h>
+
+int f(int i)
+{
+  i -= 2 * (INT_MAX + 1);
+  return i;
+}