From 8c9004573aae3886048b090c5c474ed30e0bde36 Mon Sep 17 00:00:00 2001 From: Gabor Loki Date: Tue, 10 May 2005 13:47:05 +0000 Subject: re PR c++/17913 (ICE jumping into statement expression) 2005-05-10 Gabor Loki PR c/17913 * c-typeck.c (build_conditional_expr): Remove reducing cond_expr. * fold-const.c (fold): Expand the condition of reducing cond_expr. (contains_label_1, contains_label_p): New functions for checking labels in a sub-tree. testsuite: 2005-05-10 Gabor Loki PR c/17913 * gcc.c-torture/compile/pr17913.c: Computed jump test for PR17913 From-SVN: r99514 --- gcc/fold-const.c | 41 ++++++++++++++++++++++++++++++++++++++--- 1 file changed, 38 insertions(+), 3 deletions(-) (limited to 'gcc/fold-const.c') diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 140f940..0f3c8dd 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -9905,6 +9905,37 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) } /* switch (code) */ } +/* Callback for walk_tree, looking for LABEL_EXPR. + Returns tree TP if it is LABEL_EXPR. Otherwise it returns NULL_TREE. + Do not check the sub-tree of GOTO_EXPR. */ + +static tree +contains_label_1 (tree *tp, + int *walk_subtrees, + void *data ATTRIBUTE_UNUSED) +{ + switch (TREE_CODE (*tp)) + { + case LABEL_EXPR: + return *tp; + case GOTO_EXPR: + *walk_subtrees = 0; + /* no break */ + default: + return NULL_TREE; + } +} + +/* Checks wheter the sub-tree ST contains a label LABEL_EXPR which is + accessible from outside the sub-tree. Returns NULL_TREE if no + addressable label is found. */ + +static bool +contains_label_p (tree st) +{ + return (walk_tree (&st, contains_label_1 , NULL, NULL) != NULL_TREE); +} + /* Fold a ternary expression of code CODE and type TYPE with operands OP0, OP1, and OP2. Return the folded expression if folding is successful. Otherwise, return NULL_TREE. */ @@ -9958,12 +9989,16 @@ fold_ternary (enum tree_code code, tree type, tree op0, tree op1, tree op2) so all simple results must be passed through pedantic_non_lvalue. */ if (TREE_CODE (arg0) == INTEGER_CST) { + tree unused_op = integer_zerop (arg0) ? op1 : op2; tem = integer_zerop (arg0) ? op2 : op1; /* Only optimize constant conditions when the selected branch has the same type as the COND_EXPR. This avoids optimizing - away "c ? x : throw", where the throw has a void type. */ - if (! VOID_TYPE_P (TREE_TYPE (tem)) - || VOID_TYPE_P (type)) + away "c ? x : throw", where the throw has a void type. + Avoid throwing away that operand which contains label. */ + if ((!TREE_SIDE_EFFECTS (unused_op) + || !contains_label_p (unused_op)) + && (! VOID_TYPE_P (TREE_TYPE (tem)) + || VOID_TYPE_P (type))) return pedantic_non_lvalue (tem); return NULL_TREE; } -- cgit v1.1