Hi!
As mentioned inthe PR, the switch expansion relies on EDGE_SUCC (bb, 0)
from a GIMPLE_SWITCH to be the default edge, but GIMPLE only ensures that
default label is the first one.
So, this patch (in expand_case) instead finds the default_edge from the
default label and corresponding block.
Another issue is emit_case_dispatch_table - this function is called from
expand_case as well as sjlj landing pad handling. For the former, it
suffers from a similar problem, and additionally we could have removed
the default edge already, so even for switches that formerly had a default
label we suddenly consider a random different edge as the default.
For sjlj, I've just looked at one testcase in cross to hppa2.0w-hp-hpux10.0,
and I believe stmt_bb should be just NULL, in any case if it would be
non-NULL and there is some edge, it would hardly be the default edge,
since the caller is emitting the default label after the switch expansion.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2017-08-04 Jakub Jelinek <ja...@redhat.com>
PR middle-end/81698
* stmt.c (emit_case_dispatch_table): Add DEFAULT_EDGE argument,
instead of computing it in the function. Formatting fix.
(expand_case): Don't rely on default_edge being the first edge,
clear it if removing it, pass default_edge to
emit_case_dispatch_table.
(expand_sjlj_dispatch_table): Pass NULL as DEFAULT_EDGE, formatting
fix.
--- gcc/stmt.c.jj 2017-07-14 13:04:47.000000000 +0200
+++ gcc/stmt.c 2017-08-04 14:36:28.936447265 +0200
@@ -945,8 +945,8 @@ conditional_probability (profile_probabi
static void
emit_case_dispatch_table (tree index_expr, tree index_type,
struct case_node *case_list, rtx default_label,
- tree minval, tree maxval, tree range,
- basic_block stmt_bb)
+ edge default_edge, tree minval, tree maxval,
+ tree range, basic_block stmt_bb)
{
int i, ncases;
struct case_node *n;
@@ -954,7 +954,6 @@ emit_case_dispatch_table (tree index_exp
rtx_insn *fallback_label = label_rtx (case_list->code_label);
rtx_code_label *table_label = gen_label_rtx ();
bool has_gaps = false;
- edge default_edge = stmt_bb ? EDGE_SUCC (stmt_bb, 0) : NULL;
profile_probability default_prob = default_edge ? default_edge->probability
: profile_probability::never
();
profile_probability base = get_outgoing_edge_probs (stmt_bb);
@@ -1026,9 +1025,8 @@ emit_case_dispatch_table (tree index_exp
through the indirect jump or the direct conditional jump
before that. Split the probability of reaching the
default label among these two jumps. */
- new_default_prob = conditional_probability (default_prob.apply_scale
- (1, 2),
- base);
+ new_default_prob
+ = conditional_probability (default_prob.apply_scale (1, 2), base);
default_prob = default_prob.apply_scale (1, 2);
base -= default_prob;
}
@@ -1147,9 +1145,10 @@ expand_case (gswitch *stmt)
do_pending_stack_adjust ();
/* Find the default case target label. */
- default_label = jump_target_rtx
- (CASE_LABEL (gimple_switch_default_label (stmt)));
- edge default_edge = EDGE_SUCC (bb, 0);
+ tree default_lab = CASE_LABEL (gimple_switch_default_label (stmt));
+ default_label = jump_target_rtx (default_lab);
+ basic_block default_bb = label_to_block_fn (cfun, default_lab);
+ edge default_edge = find_edge (bb, default_bb);
profile_probability default_prob = default_edge->probability;
/* Get upper and lower bounds of case values. */
@@ -1245,9 +1244,10 @@ expand_case (gswitch *stmt)
{
default_label = NULL;
remove_edge (default_edge);
+ default_edge = NULL;
}
emit_case_dispatch_table (index_expr, index_type,
- case_list, default_label,
+ case_list, default_label, default_edge,
minval, maxval, range, bb);
}
@@ -1340,9 +1340,9 @@ expand_sjlj_dispatch_table (rtx dispatch
}
emit_case_dispatch_table (index_expr, index_type,
- case_list, default_label,
+ case_list, default_label, NULL,
minval, maxval, range,
- BLOCK_FOR_INSN (before_case));
+ BLOCK_FOR_INSN (before_case));
emit_label (default_label);
}
Jakub
