c++: don't fold away 'if' with constant condition
Commit Message
richi's recent unreachable code warning experiments had trouble with the C++
front end folding away an 'if' with a constant condition. Let's do less
folding at the statement level. Thanks to Marek for finding the offending
code.
Tested x86_64-pc-linux-gnu, applying to trunk.
gcc/cp/ChangeLog:
* cp-gimplify.c (genericize_if_stmt): Always build a COND_EXPR.
---
gcc/cp/cp-gimplify.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
base-commit: 92de188ea3d36ec012b6d42959d4722e42524256
@@ -166,11 +166,8 @@ genericize_if_stmt (tree *stmt_p)
can contain unfolded immediate function calls, we have to discard
the then_ block regardless of whether else_ has side-effects or not. */
if (IF_STMT_CONSTEVAL_P (stmt))
- stmt = else_;
- else if (integer_nonzerop (cond) && !TREE_SIDE_EFFECTS (else_))
- stmt = then_;
- else if (integer_zerop (cond) && !TREE_SIDE_EFFECTS (then_))
- stmt = else_;
+ stmt = build3 (COND_EXPR, void_type_node, boolean_false_node,
+ void_node, else_);
else
stmt = build3 (COND_EXPR, void_type_node, cond, then_, else_);
protected_set_expr_location_if_unset (stmt, locus);