+/* A subroutine of expand_gimple_cond. Given E, a fallthrough edge
+ of a basic block where we just expanded the conditional at the end,
+ possibly clean up the CFG and instruction sequence. */
+
+static void
+maybe_cleanup_end_of_block (edge e)
+{
+ /* Special case: when jumpif decides that the condition is
+ trivial it emits an unconditional jump (and the necessary
+ barrier). But we still have two edges, the fallthru one is
+ wrong. purge_dead_edges would clean this up later. Unfortunately
+ we have to insert insns (and split edges) before
+ find_many_sub_basic_blocks and hence before purge_dead_edges.
+ But splitting edges might create new blocks which depend on the
+ fact that if there are two edges there's no barrier. So the
+ barrier would get lost and verify_flow_info would ICE. Instead
+ of auditing all edge splitters to care for the barrier (which
+ normally isn't there in a cleaned CFG), fix it here. */
+ if (BARRIER_P (get_last_insn ()))
+ {
+ basic_block bb = e->src;
+ rtx insn;
+ remove_edge (e);
+ /* Now, we have a single successor block, if we have insns to
+ insert on the remaining edge we potentially will insert
+ it at the end of this block (if the dest block isn't feasible)
+ in order to avoid splitting the edge. This insertion will take
+ place in front of the last jump. But we might have emitted
+ multiple jumps (conditional and one unconditional) to the
+ same destination. Inserting in front of the last one then
+ is a problem. See PR 40021. We fix this by deleting all
+ jumps except the last unconditional one. */
+ insn = PREV_INSN (get_last_insn ());
+ /* Make sure we have an unconditional jump. Otherwise we're
+ confused. */
+ gcc_assert (JUMP_P (insn) && !any_condjump_p (insn));
+ for (insn = PREV_INSN (insn); insn != BB_HEAD (bb);)
+ {
+ insn = PREV_INSN (insn);
+ if (JUMP_P (NEXT_INSN (insn)))
+ delete_insn (NEXT_INSN (insn));
+ }
+ }
+}
+
+