[Bug inline-asm/93981] No EH information generated for asm statements

[jwjagersma at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93981

--- Comment #11 from jwjagersma at gmail dot com ---
(In reply to Richard Biener from comment #10)
> Some stmt-ends-BB predicates are probably off for asms.

For stmt_ends_bb_p (tree-cfg.c:2763) the call chain looks like this:

stmt_ends_bb_p -> is_ctrl_altering_stmt -> stmt_can_throw_internal ->
stmt_could_throw_p -> gimple_asm_volatile_p

So volatile asms are considered bb-enders, now that they have a landing
pad, which stmt_can_throw_internal checks for. I am not sure how
that works actually, do all throwing statements get a landing pad at
first, even if there is no try block? Because that looks to be the
case, I assume these are eliminated in some later pass.

Using gdb I found that the DEBUG stmt is added in rewrite_stmt
(tree-into-ssa.c:1417) which does so without considering if the bb has
an EH edge or not. How does this work for other throwing statements?