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[3.3.2 PATCH] Backport invalid C++ tree sharing fix + testcase
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Mark Mitchell <mark at codesourcery dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Wed, 1 Oct 2003 20:35:19 +0200
- Subject: [3.3.2 PATCH] Backport invalid C++ tree sharing fix + testcase
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
The following testcase is miscompiled on IA-32 (foo has an endless loop)
in 3.3.x.
It is a regression from 3.2.x and fixed again on the trunk.
I tracked it down to:
http://gcc.gnu.org/ml/gcc-patches/2003-07/msg01063.html
Below is backport of the patch to gcc-3_3-branch.
Ok to commit?
2003-07-09 Mark Mitchell <mark@codesourcery.com>
* cp-tree.h (break_out_calls): Remove declaration.
* tree.c (break_out_calls): Remove.
* typeck.c (build_modify_expr): Avoid invalid sharing of trees.
2003-10-01 Jakub Jelinek <jakub@redhat.com>
* g++.dg/opt/cond1.C: New test.
--- gcc/testsuite/g++.dg/opt/cond1.C.jj 2003-09-15 15:40:47.000000000 +0200
+++ gcc/testsuite/g++.dg/opt/cond1.C 2003-10-01 14:39:32.000000000 +0200
@@ -0,0 +1,24 @@
+// { dg-do run }
+// { dg-options "-O2" }
+
+struct D { int x; };
+struct W
+{
+ W () {}
+ D & operator * () { return d; }
+ D d;
+};
+
+int
+foo (int y)
+{
+ W m;
+ (*m).x = (y > 1 ? y : 0);
+ return (*m).x;
+}
+
+int
+main ()
+{
+ return (foo (6) != 6);
+}
--- gcc/cp/cp-tree.h.jj 2003-10-01 12:08:54.000000000 +0200
+++ gcc/cp/cp-tree.h 2003-10-01 22:23:33.000000000 +0200
@@ -4317,7 +4317,6 @@ extern tree build_min PARAMS ((enum t
extern tree build_min_nt PARAMS ((enum tree_code, ...));
extern tree build_cplus_new PARAMS ((tree, tree));
extern tree get_target_expr PARAMS ((tree));
-extern tree break_out_calls PARAMS ((tree));
extern tree build_cplus_method_type PARAMS ((tree, tree, tree));
extern tree build_cplus_staticfn_type PARAMS ((tree, tree, tree));
extern tree build_cplus_array_type PARAMS ((tree, tree));
--- gcc/cp/typeck.c.jj 2003-09-16 17:25:55.000000000 +0200
+++ gcc/cp/typeck.c 2003-10-01 22:23:06.000000000 +0200
@@ -5502,44 +5502,8 @@ build_modify_expr (lhs, modifycode, rhs)
if (newrhs == error_mark_node)
return error_mark_node;
- if (TREE_CODE (newrhs) == COND_EXPR)
- {
- tree lhs1;
- tree cond = TREE_OPERAND (newrhs, 0);
-
- if (TREE_SIDE_EFFECTS (lhs))
- cond = build_compound_expr (tree_cons
- (NULL_TREE, lhs,
- build_tree_list (NULL_TREE, cond)));
-
- /* Cannot have two identical lhs on this one tree (result) as preexpand
- calls will rip them out and fill in RTL for them, but when the
- rtl is generated, the calls will only be in the first side of the
- condition, not on both, or before the conditional jump! (mrs) */
- lhs1 = break_out_calls (lhs);
-
- if (lhs == lhs1)
- /* If there's no change, the COND_EXPR behaves like any other rhs. */
- result = build (modifycode == NOP_EXPR ? MODIFY_EXPR : INIT_EXPR,
- lhstype, lhs, newrhs);
- else
- {
- tree result_type = TREE_TYPE (newrhs);
- /* We have to convert each arm to the proper type because the
- types may have been munged by constant folding. */
- result
- = build (COND_EXPR, result_type, cond,
- build_modify_expr (lhs, modifycode,
- cp_convert (result_type,
- TREE_OPERAND (newrhs, 1))),
- build_modify_expr (lhs1, modifycode,
- cp_convert (result_type,
- TREE_OPERAND (newrhs, 2))));
- }
- }
- else
- result = build (modifycode == NOP_EXPR ? MODIFY_EXPR : INIT_EXPR,
- lhstype, lhs, newrhs);
+ result = build (modifycode == NOP_EXPR ? MODIFY_EXPR : INIT_EXPR,
+ lhstype, lhs, newrhs);
TREE_SIDE_EFFECTS (result) = 1;
--- gcc/cp/tree.c.jj 2003-05-16 00:06:44.000000000 +0200
+++ gcc/cp/tree.c 2003-10-01 22:24:46.000000000 +0200
@@ -375,97 +375,6 @@ get_target_expr (init)
{
return build_target_expr_with_type (init, TREE_TYPE (init));
}
-
-/* Recursively perform a preorder search EXP for CALL_EXPRs, making
- copies where they are found. Returns a deep copy all nodes transitively
- containing CALL_EXPRs. */
-
-tree
-break_out_calls (exp)
- tree exp;
-{
- register tree t1, t2 = NULL_TREE;
- register enum tree_code code;
- register int changed = 0;
- register int i;
-
- if (exp == NULL_TREE)
- return exp;
-
- code = TREE_CODE (exp);
-
- if (code == CALL_EXPR)
- return copy_node (exp);
-
- /* Don't try and defeat a save_expr, as it should only be done once. */
- if (code == SAVE_EXPR)
- return exp;
-
- switch (TREE_CODE_CLASS (code))
- {
- default:
- abort ();
-
- case 'c': /* a constant */
- case 't': /* a type node */
- case 'x': /* something random, like an identifier or an ERROR_MARK. */
- return exp;
-
- case 'd': /* A decl node */
-#if 0 /* This is bogus. jason 9/21/94 */
-
- t1 = break_out_calls (DECL_INITIAL (exp));
- if (t1 != DECL_INITIAL (exp))
- {
- exp = copy_node (exp);
- DECL_INITIAL (exp) = t1;
- }
-#endif
- return exp;
-
- case 'b': /* A block node */
- {
- /* Don't know how to handle these correctly yet. Must do a
- break_out_calls on all DECL_INITIAL values for local variables,
- and also break_out_calls on all sub-blocks and sub-statements. */
- abort ();
- }
- return exp;
-
- case 'e': /* an expression */
- case 'r': /* a reference */
- case 's': /* an expression with side effects */
- for (i = TREE_CODE_LENGTH (code) - 1; i >= 0; i--)
- {
- t1 = break_out_calls (TREE_OPERAND (exp, i));
- if (t1 != TREE_OPERAND (exp, i))
- {
- exp = copy_node (exp);
- TREE_OPERAND (exp, i) = t1;
- }
- }
- return exp;
-
- case '<': /* a comparison expression */
- case '2': /* a binary arithmetic expression */
- t2 = break_out_calls (TREE_OPERAND (exp, 1));
- if (t2 != TREE_OPERAND (exp, 1))
- changed = 1;
- case '1': /* a unary arithmetic expression */
- t1 = break_out_calls (TREE_OPERAND (exp, 0));
- if (t1 != TREE_OPERAND (exp, 0))
- changed = 1;
- if (changed)
- {
- if (TREE_CODE_LENGTH (code) == 1)
- return build1 (code, TREE_TYPE (exp), t1);
- else
- return build (code, TREE_TYPE (exp), t1, t2);
- }
- return exp;
- }
-
-}
/* Construct, lay out and return the type of methods belonging to class
BASETYPE and whose arguments are described by ARGTYPES and whose values
Jakub