[Bug c++/86769] g++ destroys condition variable in for statement too early
mpolacek at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Mon Nov 30 20:10:23 GMT 2020
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86769
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |mpolacek at gcc dot gnu.org
--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Unfinished/untested patch:
commit f873acfa7ed1956a58d02cc383b8d709c446f656 (HEAD -> PR86769)
Author: Marek Polacek <polacek@redhat.com>
Date: Fri Nov 20 16:40:50 2020 -0500
c++: Condition in for statement destroyed too early [PR86769]
diff --git a/gcc/c-family/c-gimplify.c b/gcc/c-family/c-gimplify.c
index a7c0ec3be0d..f0a19456715 100644
--- a/gcc/c-family/c-gimplify.c
+++ b/gcc/c-family/c-gimplify.c
@@ -205,6 +205,30 @@ expr_loc_or_loc (const_tree expr, location_t or_loc)
return loc;
}
+/* TODO */
+
+static bool
+maybe_inject_incr_to_body (tree body, tree incr)
+{
+ if (TREE_CODE (body) == BIND_EXPR)
+ body = BIND_EXPR_BODY (body);
+ if (TREE_CODE (body) == STATEMENT_LIST)
+ {
+ tree_stmt_iterator i = tsi_last (body);
+ tree t = tsi_stmt (i);
+ if (TREE_CODE (t) == TRY_FINALLY_EXPR)
+ {
+ if (TREE_CODE (TREE_OPERAND (t, 0)) == STATEMENT_LIST)
+ {
+ i = tsi_last (TREE_OPERAND (t, 0));
+ tsi_link_after (&i, incr, TSI_CONTINUE_LINKING);
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
/* Build a generic representation of one of the C loop forms. COND is the
loop condition or NULL_TREE. BODY is the (possibly compound) statement
controlled by the loop. INCR is the increment expression of a for-loop,
@@ -291,6 +315,9 @@ genericize_c_loop (tree *stmt_p, location_t start_locus,
tree cond, tree body,
append_to_statement_list (top, &stmt_list);
}
+ if (maybe_inject_incr_to_body (body, incr))
+ incr = NULL_TREE;
+
append_to_statement_list (body, &stmt_list);
finish_bc_block (&stmt_list, bc_continue, clab);
if (incr)
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