The middle-end warns about the ANNOTATE_EXPR added for while/for loops
if they declare a var inside of the loop condition.
This is because the assumption is that ANNOTATE_EXPR argument is used
immediately in a COND_EXPR (later GIMPLE_COND), but simplify_loop_decl_cond
wraps the ANNOTATE_EXPR inside of a TRUTH_NOT_EXPR, so it no longer
holds.
The following patch fixes that by adding the TRUTH_NOT_EXPR inside of the
ANNOTATE_EXPR argument if any.
2024-04-12 Jakub Jelinek <jakub@redhat.com>
PR c++/114691
* semantics.cc (simplify_loop_decl_cond): Use cp_build_unary_op with
TRUTH_NOT_EXPR on ANNOTATE_EXPR argument (if any) rather than
ANNOTATE_EXPR itself.
* g++.dg/ext/pr114691.C: New test.
(cherry picked from commit
91146346f57cc54dfeb2669347edd0eb3d13af7f)
*cond_p = boolean_true_node;
if_stmt = begin_if_stmt ();
- cond = cp_build_unary_op (TRUTH_NOT_EXPR, cond, false, tf_warning_or_error);
+ cond_p = &cond;
+ while (TREE_CODE (*cond_p) == ANNOTATE_EXPR)
+ cond_p = &TREE_OPERAND (*cond_p, 0);
+ *cond_p = cp_build_unary_op (TRUTH_NOT_EXPR, *cond_p, false,
+ tf_warning_or_error);
finish_if_stmt_cond (cond, if_stmt);
finish_break_stmt ();
finish_then_clause (if_stmt);
--- /dev/null
+// PR c++/114691
+// { dg-do compile }
+// { dg-options "-O2 -Wall" }
+
+void qux (int);
+int foo (int);
+
+void
+bar (int x)
+{
+ #pragma GCC ivdep
+ while (int y = foo (x)) // { dg-bogus "ignoring loop annotation" }
+ qux (y);
+}
+
+void
+baz (int x)
+{
+ #pragma GCC ivdep
+ for (; int y = foo (x); ) // { dg-bogus "ignoring loop annotation" }
+ qux (y);
+}