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Java: Fix double-evaluation of RHS of array store


Adam found a bug where we are evaluating an array store RHS twice, 
resulting in two calls instead of one. This is because if the RHS is not 
a save_expr, it will get re-evaluated when determining its type for 
store checking.

In many cases a call_expr RHS is already wrapped by a save_expr, which 
is why I didn't notice this before.

Rebuilt libjava and ran testsuite without regressions on PowerPC linux. 
I'm checking this in as an obvious fix.

regards

Bryce.

2002-03-11  Bryce McKinlay  <bryce@waitaki.otago.ac.nz>

	* parse.y (patch_assignment): Wrap the right-hand-side with a save_expr
	to prevent it getting evaluated twice in the store checking case.
	* expr.c (build_java_arraystore_check): Unwrap SAVE_EXPR's when
	examining OBJECT.

Index: parse.y
===================================================================
RCS file: /cvs/gcc/egcs/gcc/java/parse.y,v
retrieving revision 1.357
diff -u -r1.357 parse.y
--- parse.y	2002/03/09 16:31:51	1.357
+++ parse.y	2002/03/11 10:42:52
@@ -12715,6 +12715,9 @@
       && JREFERENCE_TYPE_P (TYPE_ARRAY_ELEMENT (lhs_type)))
     {
       tree array, store_check, base, index_expr;
+      
+      /* Save RHS so that it doesn't get re-evaluated by the store check. */ 
+      new_rhs = save_expr (new_rhs);
 
       /* Get the INDIRECT_REF. */
       array = TREE_OPERAND (TREE_OPERAND (lvalue, 0), 0);
Index: expr.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/java/expr.c,v
retrieving revision 1.136
diff -u -r1.136 expr.c
--- expr.c	2002/03/08 20:59:51	1.136
+++ expr.c	2002/03/11 10:42:54
@@ -811,7 +811,7 @@
    tree array; 
    tree object;
 {
-  tree check, element_type;
+  tree check, element_type, source;
   tree array_type_p = TREE_TYPE (array);
   tree object_type = TYPE_NAME (TREE_TYPE (TREE_TYPE (object)));
 
@@ -837,11 +837,17 @@
 	  || CLASS_FINAL (element_type)))
     return build1 (NOP_EXPR, array_type_p, array);
   
+  /* OBJECT might be wrapped by a SAVE_EXPR. */
+  if (TREE_CODE (object) == SAVE_EXPR)
+    source = TREE_OPERAND (object, 0);
+  else
+    source = object;
+  
   /* Avoid the check if OBJECT was just loaded from the same array. */
-  if (TREE_CODE (object) == ARRAY_REF)
+  if (TREE_CODE (source) == ARRAY_REF)
     {
       tree target;
-      tree source = TREE_OPERAND (object, 0); /* COMPONENT_REF. */
+      source = TREE_OPERAND (source, 0); /* COMPONENT_REF. */
       source = TREE_OPERAND (source, 0); /* INDIRECT_REF. */
       source = TREE_OPERAND (source, 0); /* Source array's DECL or SAVE_EXPR. */
       if (TREE_CODE (source) == SAVE_EXPR)

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