> Did you see the inline comments?
I missed them, sorry :)
This is updated patch I am testing.
Index: except.c
===================================================================
--- except.c (revision 250312)
+++ except.c (working copy)
@@ -2444,6 +2444,61 @@ emit_note_eh_region_end (rtx_insn *insn)
return emit_note_after (NOTE_INSN_EH_REGION_END, insn);
}
+/* Add NOP after NOTE_INSN_SWITCH_TEXT_SECTIONS when the cold section starts
+ with landing pad.
+ With landing pad being at offset 0 from the start label of the section
+ we would miss EH delivery because 0 is special and means no landing pad. */
+
+bool
+maybe_add_nop_after_section_switch (void)
+{
+ if (!crtl->uses_eh_lsda
+ || !crtl->eh.call_site_record_v[1])
+ return false;
+ int n = vec_safe_length (crtl->eh.call_site_record_v[1]);
+ hash_set<rtx_insn *> visited;
+
+ for (int i = 0; i < n; ++i)
+ {
+ struct call_site_record_d *cs
+ = (*crtl->eh.call_site_record_v[1])[i];
+ if (cs->landing_pad)
+ {
+ rtx_insn *insn = as_a <rtx_insn *> (cs->landing_pad);
+ while (true)
+ {
+ /* Landing pads have LABEL_PRESERVE_P flag set. This check make
+ sure that we do not walk past landing pad visited earlier
+ which would result in possible quadratic behaviour. */
+ if (LABEL_P (insn) && LABEL_PRESERVE_P (insn)
+ && visited.add (insn))
+ break;
+
+ /* Conservatively assume that ASM insn may be empty. We have
+ now way to tell what they contain. */
+ if (active_insn_p (insn)
+ && GET_CODE (PATTERN (insn)) != ASM_INPUT
+ && GET_CODE (PATTERN (insn)) != ASM_OPERANDS)
+ break;
+
+ /* If we reached the start of hot section, then NOP will be
+ needed. */
+ if (GET_CODE (insn) == NOTE
+ && NOTE_KIND (insn) == NOTE_INSN_SWITCH_TEXT_SECTIONS)
+ {
+ emit_insn_after (gen_nop (), insn);
+ break;
+ }
+
+ /* We visit only labels from cold section. We should never hit
+ begining of the insn stream here. */
+ insn = PREV_INSN (insn);
+ }
+ }
+ }
+ return false;
+}
+
/* Turn REG_EH_REGION notes back into NOTE_INSN_EH_REGION notes.
The new note numbers will not refer to region numbers, but
instead to call site entries. */
@@ -2466,6 +2521,8 @@ convert_to_eh_region_ranges (void)
rtx_insn *last_no_action_insn_before_switch = NULL;
int saved_call_site_base = call_site_base;
+ maybe_add_nop_after_section_switch ();
+
vec_alloc (crtl->eh.action_record_data, 64);
for (iter = get_insns (); iter ; iter = NEXT_INSN (iter))
