On 11/25/2017 07:22 PM, Jakub Jelinek wrote:
On Sat, Nov 25, 2017 at 10:01:22AM +0100, Jakub Jelinek wrote:
Actually, thinking about it some more, maybe it would be more efficient
to gather this information during construction of the SWITCH_STMT in some
new flag on the tree, so cxx_block_may_fallthru would just:
Here it is implemented, bootstrapped/regtested on x86_64-linux and
i686-linux, ok for trunk?
nice.
--- gcc/cp/cp-tree.h.jj 2017-11-17 08:40:32.000000000 +0100
+++ gcc/cp/cp-tree.h 2017-11-25 21:25:48.277897180 +0100
+/* Set if the body of a switch stmt contains a default: case label
+ and does not contain any break; stmts, thus if SWITCH_STMT_BODY
+ is not empty and doesn't fallthru, then the whole SWITCH_STMT
+ can't fallthru either. */
+#define SWITCH_STMT_CANNOT_FALLTHRU_P(NODE) \
+ TREE_LANG_FLAG_0 (SWITCH_STMT_CHECK (NODE))
The macro name isn't quite right. As the comment says, it's not
sufficient that this flag is set for the switch to not fall through --
the switch body must be non-empty (which I presume it cannot be as there
must be a default label), and it cannot fall through in its own right.
The semantics of this flag are more like SWITCH_STMT_COVERS_ALL_CASES,
perhaps something of that ilk would be a clearer name?
nathan
--
Nathan Sidwell
