Fix PR66178, ICE due to misexpansion of constant expressions involving labels.

	PR middle-end/66178
	* expr.c (expand_expr_real_2) [PLUS_EXPR, MINUS_EXPR]: Don't
	drop EXPAND_INITIALIZER.
	* rtl.h (contains_symbolic_reference_p): Declare.
	* rtlanal.c (contains_symbolic_reference_p): New function.
	* simplify-rtx.c (simplify_binary_operation_1): Don't turn
	a subtraction into a NOT if symbolic constants are involved.

testsuite/
	PR middle-end/66178
	gcc.dg/torture/pr66178.c: New test.

From-SVN: r232689

gcc/ChangeLog

+2016-01-21  Bernd Schmidt  <bschmidt@redhat.com>
+
+	PR middle-end/66178
+	* expr.c (expand_expr_real_2) [PLUS_EXPR, MINUS_EXPR]: Don't
+	drop EXPAND_INITIALIZER.
+	* rtl.h (contains_symbolic_reference_p): Declare.
+	* rtlanal.c (contains_symbolic_reference_p): New function.
+	* simplify-rtx.c (simplify_binary_operation_1): Don't turn
+	a subtraction into a NOT if symbolic constants are involved.
+
 2016-01-21  Anton Blanchard  <anton@samba.org>
 	    Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
 

gcc/expr.c

@@ -8381,11 +8381,11 @@ expand_expr_real_2 (sepops ops, rtx target, machine_mode tmode,
 	 if it's all in the wrong mode to form part of an address.
 	 And force_operand won't know whether to sign-extend or
 	 zero-extend.  */
-      if ((modifier != EXPAND_SUM && modifier != EXPAND_INITIALIZER)
-	  || mode != ptr_mode)
+      if (modifier != EXPAND_INITIALIZER
+	  && (modifier != EXPAND_SUM || mode != ptr_mode))
 	{
 	  expand_operands (treeop0, treeop1,
-			   subtarget, &op0, &op1, EXPAND_NORMAL);
+			   subtarget, &op0, &op1, modifier);
 	  if (op0 == const0_rtx)
 	    return op1;
 	  if (op1 == const0_rtx)
@@ -8424,8 +8424,8 @@ expand_expr_real_2 (sepops ops, rtx target, machine_mode tmode,
 	 if it's all in the wrong mode to form part of an address.
 	 And force_operand won't know whether to sign-extend or
 	 zero-extend.  */
-      if ((modifier != EXPAND_SUM && modifier != EXPAND_INITIALIZER)
-	  || mode != ptr_mode)
+      if (modifier != EXPAND_INITIALIZER
+	  && (modifier != EXPAND_SUM || mode != ptr_mode))
 	goto binop;
 
       expand_operands (treeop0, treeop1,

gcc/rtl.h

@@ -2931,6 +2931,7 @@ extern void set_insn_deleted (rtx);
 
 extern rtx single_set_2 (const rtx_insn *, const_rtx);
 extern bool contains_symbol_ref_p (const_rtx);
+extern bool contains_symbolic_reference_p (const_rtx);
 
 /* Handle the cheap and common cases inline for performance.  */
 

gcc/rtlanal.c

@@ -6243,6 +6243,19 @@ contains_symbol_ref_p (const_rtx x)
   return false;
 }
 
+/* Return true if RTL X contains a SYMBOL_REF or LABEL_REF.  */
+
+bool
+contains_symbolic_reference_p (const_rtx x)
+{
+  subrtx_iterator::array_type array;
+  FOR_EACH_SUBRTX (iter, array, x, ALL)
+    if (SYMBOL_REF_P (*iter) || GET_CODE (*iter) == LABEL_REF)
+      return true;
+
+  return false;
+}
+
 /* Return true if X contains a thread-local symbol.  */
 
 bool

gcc/simplify-rtx.c

@@ -2277,8 +2277,11 @@ simplify_binary_operation_1 (enum rtx_code code, machine_mode mode,
       if (!HONOR_SIGNED_ZEROS (mode) && trueop0 == CONST0_RTX (mode))
 	return simplify_gen_unary (NEG, mode, op1, mode);
 
-      /* (-1 - a) is ~a.  */
-      if (trueop0 == constm1_rtx)
+      /* (-1 - a) is ~a, unless the expression avoids symbolic constants,
+	 in which case not retaining additions and subtractions could
+	 cause invalid assembly to be produced.  */
+      if (trueop0 == constm1_rtx
+	  && !contains_symbolic_reference_p (op1))
 	return simplify_gen_unary (NOT, mode, op1, mode);
 
       /* Subtracting 0 has no effect unless the mode has signed zeros

gcc/testsuite/ChangeLog

+2016-01-21  Bernd Schmidt  <bschmidt@redhat.com>
+
+	PR middle-end/66178
+	* gcc.dg/torture/pr66178.c: New test.
+
 2016-01-21  Anton Blanchard  <anton@samba.org>
 	    Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
 

gcc/testsuite/gcc.dg/torture/pr66178.c

+/* { dg-do compile } */
+int test(void)
+{
+    static int a =  ((char *)&&l1-(char *)&&l2)-1;
+l1:
+l2:
+    return a;
+}
+
+int test2(void)
+{
+    static int a =  ((char *)&&l2-(char *)&&l3)+((char *)&&l1-(char *)&&l2);
+l1:
+l2:
+l3:
+    return a;
+}