re PR c/7411 (cistore.c:392: Internal compiler error in…

re PR c/7411 (cistore.c:392: Internal compiler error in instantiate_virtual_regs_1, at function.c:3974)

 PR c/7411
 * expr.c (expand_expr) [PLUS]: Simplify after the operands
 have been expanded in EXPAND_NORMAL mode.

Co-Authored-By: Volker Reichelt <reichelt@igpm.rwth-aachen.de>

From-SVN: r57882

gcc/ChangeLog

+2002-09-25  Eric Botcazou  <ebotcazou@libertysurf.fr>
+            Volker Reichelt <reichelt@igpm.rwth-aachen.de>
+
+	PR c/7411
+	* expr.c (expand_expr) [PLUS]: Simplify after the operands
+	have been expanded in EXPAND_NORMAL mode.
+
 2002-10-06  Richard Henderson  <rth@redhat.com>
 
 	* config/rs6000/rs6000.md (load_toc_v4_PIC_2): Fix base constraint.

gcc/expr.c

@@ -7899,16 +7899,23 @@ expand_expr (exp, target, tmode, modifier)
 	    }
 	}
 
+      if (! safe_from_p (subtarget, TREE_OPERAND (exp, 1), 1))
+	subtarget = 0;
+
       /* No sense saving up arithmetic to be done
 	 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)
-	goto binop;
-
-      if (! safe_from_p (subtarget, TREE_OPERAND (exp, 1), 1))
-	subtarget = 0;
+	{
+	  op0 = expand_expr (TREE_OPERAND (exp, 0), subtarget, VOIDmode, 0);
+	  op1 = expand_expr (TREE_OPERAND (exp, 1), NULL_RTX, VOIDmode, 0);
+	  temp = simplify_binary_operation (PLUS, mode, op0, op1);
+	  if (temp)
+	    return temp;
+	  goto binop2;
+	}
 
       op0 = expand_expr (TREE_OPERAND (exp, 0), subtarget, VOIDmode, modifier);
       op1 = expand_expr (TREE_OPERAND (exp, 1), NULL_RTX, VOIDmode, modifier);

gcc/testsuite/gcc.c-torture/compile/20021007-1.c

+/* PR c/7411 */
+/* Verify that GCC simplifies the null addition to i before
+   virtual register substitution tries it and winds up with
+   a memory to memory move.  */
+                        
+void foo ()     
+{
+   int i = 0,j;
+ 
+   i+=j=0;
+}